Avian Influenza in Poultry

Avian influenza is a viral disease affecting the respiratory, digestive and/or nervous system of many species of birds. Avian influenza virus infection can occur in most, if not all, species of birds, both domestic and wild. Influenza viruses vary widely in their ability to cause disease (pathogenicity) and their ability to spread among birds. Wild species of birds usually do not develop clinical disease, but some influenza viruses cause severe illness or death in chickens, turkeys and guinea fowl.

History

A highly pathogenic form of avian influenza was known as "fowl plague". It first appeared in Italy more than 100 years ago (around 1878). Pathogenic avian influenza was first recognized in the United States in 1924-25. It occurred again in 1929. It was eradicated both times.

A major epidemic of highly pathogenic avian influenza occurred in the northeastern United States in 1983-84. It took more than 2 years to eradicate, at a cost of more than 70 million dollars. Approximately 17 million birds had to be destroyed during the eradication effort.

The United States has not had a major outbreak of highly pathogenic avian influenza since 1986, although less pathogenic strains of avian influenza virus are present and have caused significant losses in the poultry industry. Another major outbreak of highly pathogenic avian influenza would be disastrous to the American poultry industry.

In 1996-97 a number of table-egg farms in Lancaster and Lebanon Counties, PA tested positive for H7N2 avian influenza. Thus far, the avian influenza virus which has been detected by serologic means and/or virus isolation has been characterized as nonpathogenic to chickens, but the outbreak has had devastating effects on the local poultry industry. Between the first week of December 1996 and June 6 1997 nine flocks were depopulated. The Pennsylvania Agricultural Department imposed a quarantine on a 75-square-mile area restricting movement of poultry or poultry products into or off of operations in the area of the quarantine.

Clinical Signs

The severity of the disease ranges from inapparent (mild) to rapidly fatal. Lethal strains of the virus can strike so quickly, particularly in young chickens, that there may be no clinical signs other than sudden death.

Avian influenza viruses of low to moderate pathogenicity are identified regularly in the United States in the domestic poultry populations. Avian influenza virus is reintroduced into domestic poultry by migratory waterfowl, which are carriers of the influenza virus.

Clinical signs vary greatly and depend on many factors including the age and species of poultry affected, husbandry practices, and the inherent pathogenicity of the influenza virus strain. Clinical signs may include:

• ruffled feathers

• soft-shelled eggs

• depression and droopiness

• sudden drop in egg production

• loss of appetite

• cyanosis (purplish-blue coloring) of wattles and comb

• edema and swelling of head, eyelids, comb, wattles, and hocks

• diarrhea

• blood-tinged discharge from nostrils

• incoordination, including loss of ability to walk and stand

• pin-point hemorrhages (most easily seen on the feet and shanks)

• respiratory distress

• increased death losses in a flock

The clinical signs of avian influenza are similar to those of other avian diseases. Avian influenza may be confused with infectious bronchitis, infectious laryngotracheitis, fowl cholera, and the various forms of Newcastle disease.

Typical history, signs, and lesions may be suggestive of mild forms of avian influenza. Confirmation of a diagnosis is by serologic testing and virus isolation and identification. Because virulent strains of avian influenza are considered to be exotic to the United States, they are reportable to the USDA. Virulence level is evaluated by virus isolation and controlled laboratory challenge of experimental chickens.

Postmortem Lesions

Lesions vary greatly depending on pathogenicity of the virus, age of the bird, type of poultry, etc. Lesions may include swelling of the face and area below the beak. Removing skin from the carcass will show a clear straw-colored fluid in the subcutaneous tissues.

Blood vessels are usually engorged. Hemorrhage may be seen in the trachea, proventriculus, beneath the lining of the gizzard, and throughout the intestines. The lining of the gizzard may be easily removed.

Other areas likely to show swelling and hemorrhages include the muscle along the breast bone as well as in the heart, gizzard fat, and abdominal fat.

Young broilers may show signs of severe dehydration with other lesions less pronounced or absent entirely.

Serotypes

There are many different strains (serotypes) of the avian influenza virus. Some of the highly virulent strains evolved from milder strains following repeated chicken to chicken passages. The avian influenza virus has been shown to mutate at an extremely high rate as it serially infects poultry. Chickens are not the normal host for avian influenza, so the virus they pick up from other birds has a tendency to mutate and become pathogenic. In 1994, an avian influenza outbreak in Mexico started out mildly, but mutated into a "killer" virus that decimated many poultry flocks. This same scenario had occurred in the northeastern United States in the mid-1980s. Today, extreme biosecurity precautions prevent spread of the virus to the United States and neighboring countries in Central America. Current research efforts on avian influenza are directed toward understanding why and how mildly pathogenic viruses become highly pathogenic.

Avian influenza viruses are subdivided into serotypes based on their hemagglutinin (H) and neuraminidase (N) surface antigens. The highly pathogenic serotype of avian influenza responsible for the 1983-84 outbreak in the United States and the 1994 outbreak in Mexico was H5N2. Historically, serotypes including H5 and H7 are associated with disease in poultry.

Transmission

Infected birds shed the virus in fecal and oculo-nasal discharges. Even though recovered flocks shed less virus than clinically ill flocks, recovered flocks will intermittently shed and should be considered infected for life.

Waterfowl (wild and domesticated) are the primary natural reservoir of influenza viruses. Wild waterfowl usually do not show clinical signs, but they can excrete the virus for long periods of time. In addition, waterfowl can be infected with more than one type of influenza virus. Detection is further complicated by the fact that they often do not develop a detectable antibody response after exposure to the virus.

Influenza virus has been recovered from water and organic material from lakes and ponds utilized by infected ducks. Co-mingling of these birds with range-reared flocks is a factor in some outbreaks.

The avian influenza virus can remain viable for long periods of time at moderate temperatures, and can survive indefinitely in frozen material. As a result, the disease can be spread through improper disposal of infected carcasses, manure, or poultry by-products.

The disease also can be easily spread by people and equipment contaminated with avian influenza virus. Avian influenza viruses can be transmitted on contaminated shoes, clothing, crates, egg flats, egg cases, vehicles, and other equipment. Any object located on an infected poultry farm must be considered contaminated and should be completely cleaned and disinfected before it is moved from that premises. Clothing worn on an infected farm should be laundered.

Insects and rodents may mechanically carry the virus from infected to susceptible poultry.

Influenza virus has been isolated from turkey eggs suggesting vertical transmission, although typically the virus kills the embryo. There is little or no evidence of egg-borne infection of poults. However, eggshell surfaces can be contaminated with the influenza virus, and thus are a means of transmission.

Avian influenza viruses have frequently been isolated from clinically normal, imported exotic birds. These infected birds are a potential threat to cage birds, wild birds, and poultry.

Live-bird markets are a reservoir of infection. Such markets serve as a focal point for gathering and housing many species of bird. These facilities are rarely cleaned or disinfected.

Treatment

There is no effective treatment for avian influenza. However, good husbandry, proper nutrition, and broad spectrum antibiotics may reduce losses from secondary infections. It must be remembered that recovered flocks continue to intermittently shed the virus.

All buildings should be cleaned and disinfected after an infected flock is removed. The poultry litter or manure should be composted before application to cultivated lands.

Prevention

A vaccination program, in conjunction with strict quarantine, has been used to control mild forms of the disease in commercial chicken and turkey flocks. With the more lethal forms of the disease, however, strict quarantine and rapid depopulation of infected flocks remains the only effective methods of stopping avian influenza. The success of such a program depends, of course, on the full cooperation and support of the poultry and allied industries.

With the realization that there is a reservoir of influenza virus in wild waterfowl, every effort must be made to prevent direct or indirect contact between domestic poultry and wild waterfowl. Persons handling wild game (especially waterfowl) must change clothes completely and bathe prior to entering poultry houses.

There is currently a serious and ongoing outbreak of avian influenza in Mexico. According to Mexican authorities, the highly pathogenic influenza virus has been eradicated. However, as vaccination is widespread, it is difficult serologically to confirm this report and precautions should be continued.

It is very important to prevent the spread of this disease into the United States. It is very easy to spread avian influenza on clothing and through human contact. Do not visit or go near any poultry flocks in Mexico unless proper biosecurity actions are taken.

Procedures for Killing and Dressing Home Grown Fowl

Roger D. Jacobs and Don R. Sloan²

Today, commercial broilers are processed in highly automated, quality-controlled plants located close to where the chickens are grown. These plants dress many thousands of birds daily. The same concept used by commercial processors applies to the processing of small flocks of chickens, turkeys, geese, and ducks. As in commercial poultry processing plants, cleanliness is very important. Equipment should be cleaned before, during, and after processing. Scalding water should be changed often, and all tissues to be saved should be cleaned with cold, running water.

EQUIPMENT NEEDED

The dressing and processing of home flocks does not require much equipment. In fact, most items needed can be found in the home.

Table: The preferred table is one that can be moved and with a non-absorbent top that cleans easily.

Galvanized Trash Can: Cans should hold from 5 to 20 gallons of water and can be used both for scalding and chilling of carcasses.

Stove: The stove is has two potential uses: heating water and singeing feathers--if it has a flame top. Otherwise use a butane gas torch.

Knives: Each person involved in the processing should be given a knife. The preferred knife is one with a narrow, thin blade about 6" long. A second type of knife (handy for pulling pin feathers) has no edge and a rounded point. It's a good practice to have a whetstone handy to keep poultry knives sharp.

Cardboard Boxes: Cardboard boxes are good containers to hold feathers and inedible viscera. The filled box can be buried in the ground after processing.

Brush: A small brush is useful for cleaning the finished carcass.

Small Container: The container used to chill edible viscera can be either made of metal (household cooking pan) or plastic.

Thermometer: The thermometer is used to monitor the correct temperature of scalding water.

Sturdy Support for Suspension of Fowl: The support is used when handling the birds for killing, defeathering and evisceration. A strong, stiff clothesline works quite well. Remember to suspend the birds in an area where they will not cause damage during the death struggle.

Scissors: Use sturdy scissors for cutting and trimming edible viscera: the neck, heart, gizzard, and liver.

Ropes: Ropes are used to hold the bird's feet for killing, defeathering and evisceration. Ropes are prepared by placing a 2"x2" piece of wood at one end as shown in the drawing. The other end of the rope is tied to the support. Wrap the end of the rope (with the piece of wood attached) around the legs of the bird and hook the rope behind (See Figure 1 ). When hung from the support, the legs of the bird should be about shoulder-high.

Figure 1.

SELECTION OF BIRDS TO BE PROCESSED

One or two days before processing, separate the birds you want to process out of the flock and put them in a separate pen and taken off feed 24 to 30 hours before processing. This allows for the emptying of the digestive tract to avoid food and fecal contamination during processing. Birds should be given water during this period to prevent dehydration of the tissues. Dress only healthy birds.

KILLING

Although there are several methods for killing and bleeding poultry, we only explain the "outside cut". This is the one method used commercially when the animal tissues are to be used for human consumption. To kill and bleed poultry, grasp the head of the rope suspended bird with the left hand. Place the blade of the knife just below the ear lobe, and above and behind the lower mandible or jaw. Remember to slide the blade with the right hand down through the feathers to the skin area. With the left hand, roll the head slightly to the left, exerting a slight upward pressure. Now, draw your knife across the jugular vein until you see a gush of blood. Try not to cut into the trachea (windpipe) or the esophagus--and do not apply too much pressure on the neck or you will decapitate the animal. If the knife is sharp your incision does not have to be large or need too much pressure.

With a good, clean cut across the jugular vein, bleeding takes about 3 minutes. Just before expiration, the bird will flap its wings vigorously. MAKE SURE THE BIRD IS DEAD BEFORE YOU BEGIN SCALDING.

SCALDING

Scalding the carcass should be done immediately after killing and bleeding. If a carcass is allowed to cool before picking, defeathering becomes more difficult. Here are the most often-used methods of scalding:

Soft Scald: Does not cook the outer skin layer. Picking after a soft scald is more difficult, but gives a much more appealing carcass with a longer shelf life.

Sub Scald: Cooks the outer skin layer, but permits easier feather picking. Its' major drawback is increased dehydration leading to a shorter shelf life. The skin, following scalding, has a shiny appearance and is sticky to the touch as the carcass dries.

Hard Scald: This method is reserved for water fowl. When used on chickens or young fowl, the skin discolors rapidly and feels doughy to the touch.

To scald, hold the carcass by the feet, immerse it completely into the scald water. Swirl it around, up and down. (For water fowl and adult birds, a small amount of detergent can be added to the water for better water penetration and easier picking.) After scalding the carcass, pull out some of the larger wing or tail feathers--they are the most difficult to pluck. If it is too hard to remove these feathers, submerge the carcass a few more seconds. Remember to check your thermometer between immersions. If the water temperature has fallen below the numbers in the chart, reheat it. When the scalding water becomes dirty, replace it. (See Table 1.)

DEFEATHERING

Immediately following scalding, begin plucking or defeathering. Here are three methods of defeathering carcasses:

Wet Picking: Here's a useful plucking sequence: wing feathers, tail feathers, legs, breast, neck, and back.

Feathers should be pulled out against the way they normally lay. Wing and tail feathers must be pulled straight out. A gentle, rubbing action with the thumbs along the skin helps get the fluff and pin feathers. A short, rounded, blunt edge knife also is very helpful with pin feathers. Pin feathers also can be removed by applying pressure below the follicle and squeezing them out. After picking the carcass some hair-like feathers may still be present. Singe those using a flame-type range or a bottle gas torch. Singe the carcass by rotating the carcass around an open flame. BE CAREFUL NOT TO BURN THE CARCASS, YOURSELF, OR START A FIRE.

Dry Picking: Use this method when you wish to save the feathers. The method is the same as wet picking, except you leave out scalding. Immediately after the jugular vein has been cut, a procedure called debraining can be used to help loosen the feathers. To do this, push a narrow, long-bladed knife parallel with the upper mandible, through the lower brain, and into the hind brain. Twisting the knife will sever the brain stalk (See Figure 2).

Figure 2.

Wax Picking: Is used primarily for water fowl. After the carcass has been either wet- or dry-picked (and most of the feathers have been removed) dip the carcass into hot (130-160^oF) paraffin for 10-15 seconds. Have a pan of cold water handy and dip the carcass into it to harden the paraffin. Finally, peel the hardened paraffin off the carcass to remove the remaining feathers--including the pin feathers.

EVISCERATION

Once the bird has been killed, scalded, and defeathered, the carcass is called "New York Dressed." At this point you are ready to remove the head, shanks, and viscera to get to the "ready-to-cook" stage.

1. Removal of oil (or Uropygial) gland: Locate the oil gland is at the base of the tail; cut around it, remove and put it in a disposable box.

2. Removal of shank and feet: Bend the leg at the joint, between the shank and drumstick, opposite the normal bend. Cut the shank and feet off at the point by cutting through the joint.

3. Removal of head: Cut the skin and muscle tissue around the base of the skull and twist off the head.

4. Removal of neck: Cut the skin away from the neck using one of two methods:

   1. With the carcass laying on its back, push the knife from the decapitated end of the neck to the top of the breast. Push the handle of the knife downward until the point of the knife penetrates the skin. Cut towards the decapitated end of the neck.

   2. From the base of the carcass, pull the skin taut from the underside with your left hand. Slice the skin of the neck from the base of the decapitated end of the neck. Now, pull the skin away from the neck. Cut the muscle tissue around the neck where the neck joins the back. With your right hand, crimp the neck and twist off. Put the neck in a container filled with ice water and set aside for edible viscera.

5. Trachea, Esophagus and Crop: These three tissues are connected to the inside of the neck skin. If you took the bird off feed as we advised, the crop may be a little hard to find. It is a pouch associated with the esophagus. When you locate these structures, separate them from the skin and cut them away.

6. Opening the body cavity: There are various methods for opening the body cavity from the posterior end of the carcass.

   1. Cut around the cloaca (anal or vent). Be careful not to cut into the intestines.

   2. If you're trussing the carcass without string, cut around the cloaca as described, and then, make a horizonal cut across the body between the breastbone and the cloaca. After you have eviscerated and cleaned the carcass, you can push the drumstick under this flap.

   3. If you're trussing with string, make a vertical cut from the breastbone down and around the cloaca.

7. Removal of viscera: To remove the viscera, push your hand through the cloaca opening into the body cavity, loosening the upper end of the digestive tract including the bronchial tubes. Grab the gizzard and slowly pull the entrails out through the cloaca opening. The heart, lungs, kidneys, reproductive organs, and other connective tissues still remain in the body cavity. The heart, reproductive organs and connective tissue can be pulled out. The lungs are two pinkish organs embedded on the ribs on each side. They can be peeled away with your finger. The kidneys are three-lobed structures on each side, embedded in the backbone, more towards the cloaca end than were the lungs. These structures can be scraped away with a finger or stiff-bristled brush. You can finish the evisceration by washing out the carcass with clean, cold water and pulling out any other tissues. You can pre-chill the carcass by placing it in a container filled with tap water. (Let the water overflow or change the water frequently.) This procedure brings the carcass temperature down to that of tap water and helps clean the carcass.

8. Edible viscera: Normally, four tissues are considered edible viscera: neck, heart, liver and gizzard. As each tissue is processed place it in a container with ice water.

   1. Neck: The removal of the neck from the carcass was discussed earlier. Cut off any unattractive tissues.

   2. Heart: To clean the heart, cut off the vascular tissue associated with it and slip it out of the pericardial sac that surrounds the heart. If you gently squeeze on this tissue, any remaining blood will come out. Then, wash the heart in cold water.

   3. Liver: Lift the liver, being careful not to rupture the gall bladder attached. Carefully cut or pinch off the gall bladder at the neck of the bile duct, and trim off any other tissues.

   4. Gizzard: Trim off the digestive tract, split the gizzard with a sharp knife, wash away any feed, with your finger, peel off the yellow tough lining. Peeling off the inner lining is easy if you allow it to chill in ice water before trimming and washing.

CHILLING

After processing is over, place all the carcasses in a container of ice and water. This container can be the same one you used for scalding and pre-chilling. If you do use these containers, clean them with hot, soapy water, and rinsed well before use. Before you package or consume your fowl, the carcass should be brought down to a temperature of 40^oF. The time required to do this is dependent on the number and types of birds processed. Broilers can chill in only a few hours, turkeys may require up to 24 hours.

For more information on procedures for cutting up chickens, ask your County Extension Office for University of Florida Publication EHE 198 "Stretch Food Dollars by Cutting up Your Own Chickens" or Publication HFS 830 "The Cost of Poultry - Whole and Precut Selected Parts Products." For information on freezing poultry, refer to USDA Home and Garden Bulletin "Home Freezing of Poultry", Number 70.

REFERENCES

Bigbee, Daniel E., Home Processing of Chickens, University of Nebraska, Extension Publication HEG81-144.

Maurer, Arthur J., Home Slaughter of Poultry, University of Wisconsin, Extension Publication A1478.

Tables

Table 1.

Table 1. Characteristics of soft scald, sub scald, and hard scald
Method	Temperature	Immersion Time	Carcass type
Soft Scald	120-130oF	30-75 seconds	Broilers, roasters and young turkeys
Sub Scald	138-140oF	30-75 seconds	Mature chickens and turkeys
Hard Scald	160-180oF	30-60 seconds	Ducks and geese

Footnotes

1.

This document is SSPS8, one of a series of the Animal Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date April, 1995. Reviewed June, 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.

2.

Roger D. Jacobs, Area Poultry Extension Agent, Dairy and Poultry Sciences Department; Don R. Sloan, associate professor, Dairy and Poultry Sciences Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

The Home Broiler Chicken Flock 1

Jacqueline P. Jacob and F. Ben Mather²

Broilers are meat-type chickens. Sometimes they are called fryers or frying chicken. Commercial broilers are crossbreds, primarily involving White Cornish and White Plymouth Rock. Today's commercial broilers are marketed at 4-10 weeks of age, depending on the body weight desired. Broilers are used for products such as Cornish Hens (2.85 lb live weight at about 4 weeks of age), chicken for fast food restaurants (4.1 lb at about 6 weeks of age), chicken for grocery stores (6.0 lb at about 7.5 weeks of age), and deboned chicken for sandwiches, nuggets, etc. (6.5 lb at about 8.5 weeks of age).

Many families are interested in producing their own broilers for home consumption (for home processing of broilers refer to Factsheet PS-8, Procedures for Killing and Dressing Home Grown Fowl ). It may cost more to raise broilers than to buy them at the supermarket, but the recreation and satisfaction derived offset the higher cost. In addition, manure and litter from broiler production can be used to fertilize the family garden and flower beds (refer to Factsheet PS-1, Poultry Manure as a Fertilizer ).

Broiler projects are popular with 4-H and FFA members and are an integral part of many youth livestock shows. Broiler projects are especially suitable for youngsters with limited space.

Remember that home flocks, even small ones, require daily care, including weekends, vacations, and holidays. The time and effort required for this care should be considered when deciding whether or not to start a poultry flock of any kind. It is also important to check on zoning regulations in your area.

Equipment Required

Expensive housing and equipment are not necessary. However, you will need:

• a clean, dry structure that will protect your broilers from predators, cold and rain, or hot sun

• a brooder or heat lamp(s) to warm the chicks

• feeding and watering equipment

Housing

Broilers reared for home use should have 1 square foot of floor space per bird. Almost any small building that meets the floor space requirements for the size of flock desired can be used. A small number of chicks can even be brooded in a corner of a garage. Most poultry meat birds are raised under total confinement, although some flocks are allowed access to a limited amount of fenced range or yard area.

Remove all sticks, boards, and sharp objects from the broiler pen. This will reduce the likelihood of your birds getting injured.

Never place chicks on a slick surface such as cardboard, plastic or newspaper. The smooth surface may result in spraddled legs or other leg problems. Bedding material is usually placed on the floor for the chicks. In addition to providing a non-slick surface for the chicks, it absorbs the moisture from the manure and helps to maintain a "clean" environment. Wood shavings, cane fiber, ground corncobs, peanut hulls or rice hulls make good litter. Hay or straw make very poor litter and should not be used.

Brooder

Baby chicks need heat during the first few weeks of life because they cannot yet adequately regulate their body temperature. This is known as the "brooding period". The area where they are kept during this time is referred to as the "brooder". It is important that the chicks have enough room to move toward or away from the heat source and thereby find their own comfort zone.

Electric brooders are available for brooding small numbers of chicks. Electric heat lamps or infrared bulbs are also good sources of heat for brooding chicks. If infrared bulbs are used, two 125-watt bulbs per 50 chicks are recommended. Make certain the lamps are secured so they cannot fall to the litter and create a fire hazard. Use porcelain sockets approved for these lamps and suspend the lamps with a chain or wire (not the electric cord). The lamps should hang so the bottoms are 18 inches from the litter. Raise the lamps 2 inches per week to a maximum height of 24 inches. Place watering pans a good distance from the lamps to prevent splashed water from cracking the hot bulbs. Make sure you have a spare bulb.

With infrared lamps you are heating the chicks and floor only and not the air, so air temperature measurements cannot be used as a guide to chick comfort. The chick is the best thermometer available. Observe the chicks to gauge their level of comfort. If they crowd together under the lamp or are huddled and peeping, increase the heat by lowering the lamp, increasing the wattage, or by adding a second lamp. If the chicks tend to move away from the heat source, or are panting with their beaks open, reduce the heat by raising the level of the lamp or reducing the wattage. Watch your chicks closely for the first few days and nights to be sure they are comfortable. Adjust the lamps if they are not.

After the broilers are 3 to 5 weeks old and fully feathered, heat is seldom required. It will depend, of course, on the temperature in their pen. Some exhibitors tend to keep their birds much too warm. This will affect feathering, flock uniformity, fleshing and finish. The ideal growing temperature is 60° to 75°F after the broilers pass 4 weeks of age. Supplemental heat may be needed in cold weather. In hot weather, use fans to move air across the broilers.

Feeding and Watering Equipment

Supply enough feed and waterer space for all broilers to be able to eat at the same time. You can purchase feeders from the store, or make your own. For the first day or two you should use a shallow pan or an egg carton without a lid to make it easier for the chicks to find their food. After a few days, you can use an egg carton with the lid on. You will need to cut holes in the top to allow the chicks access to the feed. The holes should be about 1½ inches in diameter. Using an egg carton with the lid on will reduce the amount of feed spillage.

When the birds are older, you will need a bigger feeder, such as the one shown in Figure 1 . The feeder is made out of wood. The bar across the top is to prevent the birds from spilling the feed.

Figure 1 .

A plentiful supply of cool, clean drinking water is one of the most important requirements in raising chicks. You will need to make sure your chicks will have adequate water all day long. Waterers should be placed on a wooden block to help keep them free from litter.

You can purchase a waterer from the feed store, or you can make your own from a 48 oz fruit-juice can and an aluminum pie plate. Make two holes on opposite sides of the can, about ¾ inches from the open end. Fill the can with water, place the plate on top, and turn the can over. For the first few days, you can also use a saucer with an inverted cup placed over it.

Purchasing Chicks

Good quality broiler strain chicks should be purchased from a reputable hatchery. Some families prefer to raise pullet chicks. Others buy unsexed chicks. Pullets carry more flesh over the back and breast than cockerels and will generally have a more rounded appearance to the breast, thighs, and legs. However, cockerels grow more rapidly and reach slaughter weight 1-2 weeks earlier than pullets.

Chicks are often vaccinated at the hatchery against Marek's disease. Marek's disease is a type of avian cancer caused by a virus. Chickens 2 to 16 weeks of age (i.e., prior to sexual maturity) are most susceptible. It occurs worldwide, wherever poultry are produced. It is recommended that you purchase chicks already vaccinated against Marek's disease.

Preparation

Clean and disinfect the broiler house, feeders and waterers at least 2 weeks before the chicks arrive. Wash the pen down with soap and water. Then spray a commercial disinfectant labeled for use in poultry houses.

Be prepared for the chicks 2 days in advance. Put the bedding material (e.g., wood shavings) on the floor of the cleaned and disinfected house. Turn on the heat lamps the day before the chicks are to arrive. This will allow the area time to warm up before the chicks arrive.

You need to think about how you are going to transport your chicks home. A small box will work. Cut three to four small holes along the top to make sure the chicks get enough air to breath and don't get too hot. Chicks are quite resilient, but try to handle them as gently as possible to minimize the possibility of injury.

Put litter material or some type of rough surface material for insulation and to prevent spraddled legs.

Lighting

It is often recommended to provide continuous lighting for broilers. Twenty-four hour lighting allows the broilers access to feed at all times and increases body weight, especially during the summer months. This can be done by providing continuous artificial lighting, or by supplementing natural daylight. Keep a 40-watt bulb at least 6 feet above broilers after removing heat lamps.

If there is a possibility of a power outage, with a subsequent loss of lighting, it is recommended to provide the birds with at least 1 hour of darkness a day. This will let them get accustom to the dark so they will not panic, pile up and suffocate if the power should go off.

Broilers also can be grown with fewer than 24 hours of light per day or with only natural light, but growth rate will be slower than with 23- or 24-hour lighting.

Feeding and Watering

Optimum performance of broilers is dependent on proper nutrition. It is recommended that broilers be fed a 23% protein starter diet for the first 4 weeks. They are then fed a 19% protein grower diet from 4 to 8 weeks of age. (For more information on poultry diets, refer to Factsheet PS-6, Poultry Diets for Small Flocks .) Your local feed store, however, may not carry these diets. It is absolutely essential that broiler chicks be fed a high quality broiler feed containing at least 20 percent protein. Lower protein feeds will result in lower weight gains. Do not feed a layer diet to growing chicks because of the high calcium level.

Chicks can be started on a high protein (26 to 30 percent) turkey or game bird starter to stimulate additional growth, but this may be more expensive. You can feed the higher protein feed for 2 to 4 weeks and then switch to a broiler feed for the remaining feeding period. Milk, greens, eggs, scratch feed, etc., are not needed and will probably retard early growth.

If you use a medicated feed, be sure to follow the directions on the feed tag with regards to withdrawal times. A non-medicated feed must be fed prior to slaughter to prevent the presence of drug residues in the carcass.

Young chicks do not have an innate ability to recognize food, but they do have a strong tendency to peck at small particles, both nutritious and non-nutritious. As time passes, however, pecking at inedible particles declines and pecking at food increases as they learn to respond to the consequences of consuming different items. When chicks are raised by their mother, their attention is directed towards food because they follow their mother around. Whenever she stops to peck at a food item, they gather around and join in the pecking activity.

For chickens, feeding is a social activity. Even when chicks are reared under commercial conditions, they tend to feed as a group whenever possible. If they are isolated, their food intake is depressed -- chicks kept on their own eat less in the short term compared to chicks housed with a companion.

When the chicks first arrive, the feeders should be full, but after the chicks have learned to eat, the feeders should be no more than ¾ full to prevent feed waste.

Broilers respond to attention. Walk through the broilers and stir feed three to five times per day. This will provide exercise and increase feed consumption and growth.

Chicks need a source of fresh water. Clean the waterers at least once a day. The water should be changed daily. Even clear-looking water may have an awful smell because of the feed lost in it while the chicks are drinking.

You may need to teach your chicks where the water is. Chicks are not initially able to recognize water. They have, however, a tendency to peck at flat, shiny surfaces. This results in them pecking at a pool of water and, as soon as their beak is immersed, they begin to learn to drink. If your chicks do not drink within an hour or so of their arrival, carefully dip their beaks in the water. They will quickly learn where the water is.

Health

If the litter gets wet, the wet portion should be removed and new litter put in its place. Wet litter is an excellent media for disease organism growth which can affect the health and production of the flock.

Chick feed usually contains a coccidiostat, which is a medication to prevent coccidiosis. Coccidiosis is the most common cause of death in young chicks. It is caused by single-celled organisms, called coccidia. The coccidia attack different parts of the intestinal tract, causing irritation of the lining that prevents the absorption of food. In minor outbreaks, the chicks appear droopy, have ruffled feathers, and lose weight. Severe cases result in death. It is important to keep the bedding dry and to purchase feed that contains a coccidiostat.

Blister-like lesions, called breast blisters, can develop on the keel bone area of the breast. They may be difficult to see under the feather cover but can be detected by blowing the feathers away from the breast to reveal the underlying skin. Maintaining dry litter condition, preventing overcrowding, using equipment without sharp edges, and using feeding programs that develop good body structure before heavy weights are reached, are all factors that can help reduce the incidence of breast blisters.

Feather pecking and cannibalism (birds being injured by the beaks of other birds) are other problems that may develop. Various factors such as crowding, nutrient deficiencies, inadequate ventilation, too little drinking and eating space, too much light, idleness, and the appearance of blood on an injured bird contribute to picking. Good management can frequently ward off cannibalism. If it occurs, a pick-paste remedy available at your local feed store can help reduce the incidence of feather pecking.

Internal parasites can cause poor weight gain. Roundworms (nematodes) cause the most trouble. Refer to Factsheet PS-18, Nematode Parasites of Poultry (and where to find them) , for more information on the identification and control of roundworms. A good sanitation program is usually sufficient to prevent an internal parasite problem. Remove the litter after each flock of broilers. Keep old birds separate from the broilers and do not walk into the broiler house without thoroughly cleaning shoes.

The external parasites most likely to be found on broilers are lice and mites. These parasites lower broiler quality by reducing weight gain and causing skin discolorations. Check broilers each week for these parasites. Refer to Factsheet PS-10, Common Continuous External Parasites of Poultry , for more information on the identification and control of external parasites.

Isolation from other birds is a first means of preventing disease. Restrict unnecessary traffic of people and pets to the broiler flock.

As previously stated, broiler chicks are frequently vaccinated at the hatchery against Marek's disease. Because of the short life span of broilers, no other vaccines should be necessary. If there is a heavy infestation of mosquitoes, however, it may be necessary to vaccinate against fowl pox. Fowl pox is a relatively slow-spreading viral disease of poultry of all ages. The virus is spread from bird to bird through the bites of blood-sucking insects (such as mosquitos) or through wounds and scratches by the birds when fighting. Fowl pox is characterized by raised, wart-like lesions on unfeathered areas (head, legs, vent, etc.) of the bird. Do not vaccinate, however, unless you have a problem with fowl pox on your farm or in your area. For more information on poultry vaccines, refer to Factsheet PS-36, Vaccination of Small Poultry Flocks .

Selecting for Show

Broilers are sometimes included in youth poultry shows. Preregistration is usually required. Broiler chicks are purchased in bulk from a single hatchery and distributed to registered participants on a predetermined day (6-8 weeks before the fair). In most cases the participant must locate his/her own source of feed.

Pens of two to three broilers are entered and judged on individual size, condition, and conformation, as well as pen uniformity.

Broilers should be culled continually. Small, sick, stunted, deformed or crippled birds should be removed when detected. Just prior to the show, catch the remaining broilers and select well-fleshed birds. Examine each bird carefully for physical defects that would cause them to be downgraded. These include:

A. General defects

• cuts and tears

• broken and disjointed bones

• skin or flesh bruises anywhere other than on the wing tip

• breast blisters

• insect bites

• external parasites (lice, mites or fleas)

• skin discoloration

B. Feathering defects

• an abundance of pin feathers (new feathers just coming through the skin)

• areas of skin which may be discolored because of broken quills or sunburn resulting from inadequate feathers

Note: a lack of feather covering over the keel area of well-fleshed birds is not a defect and must not be considered as such.

C. Carcass defects

• breasts which have dented, crooked or knobby breastbones, or are abnormally shaped

• backs which are narrow, crooked, humped or hunched

• lack of body depth

• legs or wings that are deformed

Note: Defects such as crooked toes or beak are not important and should be disregarded.

The following factors should be considered when selecting the birds for your exhibition pen(s).

A. Conformation.

Conformation refers to the skeletal system, or shape of the bird. This term is often mistakenly used to describe the amount and distribution of flesh on the broiler. The ideal shape of a meat bird is rectangular.

Length: The breastbone should be long, straight, free from defects such as dents or knobs and carry well forward and back between the legs. The breastbone should be parallel to the backbone.

Width: The back should be long and wide with broad spring of ribs.

Depth: The body should be full and deep. Body depth must be consistent with breast width. Length, width and depth should be well-balanced.

B. Fleshing

Fleshing refers to the amount and distribution of muscle or flesh on the broiler. The breast, thighs, and drumsticks carry the bulk of the meat and should be examined closely.

The breast meat is the most valued part of the broiler and should be given maximum consideration. The breast muscle should be wide and full throughout the length of the keel bone. The muscle should carry well up to the crest of the bone.

The thighs and drumsticks should be heavily muscled.

C. Finish

Finish refers to the amount of fat in and immediately under the skin. A moderate amount of finish on a well-fleshed broiler will improve the eye appeal. The fat deposition between feather tracts on the side of the breast is the best indication of finish. Do not confuse finish with pigmentation (skin color).

D. Skin pigmentation

Skin pigmentation results from the deposition of yellow or yellow-orange pigments in the outer skin layer. It is not an indication of finish. Only minor emphasis should be placed on pigmentation.

E. Uniformity

Each bird in a pen should be as near a carbon copy of its pen mates as possible in sex, size, confirmation, fleshing, and finish. If one bird has a defect, it will affect the rating of the entire pen.

The birds should all be clean. Properly reared broilers usually are reasonably clean. If necessary, however, the birds can be washed. Refer to Factsheet PS-34, Preparing Poultry for Show , for details on how to wash your birds.

Processing

Some youth prefer to sell their broilers live after they have taken them to a poultry show. Others prefer to prepare them for home consumption, but hesitate to because they lack knowledge of processing procedures. Factsheet PS-8, Procedures for Killing and Dressing Home Grown Fowl , gives a description of the equipment needed, and the procedures to follow for processing your birds for home consumption.

Footnotes

1.

This document is PS42, one of a series of the Animal Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date June 1998. Reviewed June 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.

2.

Jacqueline P. Jacob, poultry extension coordinator, and F. Ben Mather, poultry extension specialist, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.

Chicken diseases

Chickens are susceptible to several parasites, including lice, mites, ticks, fleas, and intestinal worms, as well as other diseases. (Despite the name, they are not affected by Chickenpox; that is a disease of humans, not chickens.)

Some of the common diseases that affect chickens are shown below:

Name	Common Name	Caused by
Aspergillosis		fungi
Avian influenza	bird flu	virus
Histomoniasis	Blackhead disease	protozoal parasite
Botulism		toxin
Cage Layer Fatigue		mineral deficiencies, lack of exercise
Campylobacteriosis		tissue injury in the gut
Coccidiosis		parasites
Colds		virus
Crop Bound		improper feeding
Dermanyssus gallinae	Red mite	parasite
Egg bound		oversized egg
Erysipelas		bacteria
Fatty Liver Hemorrhagic Syndrome		high-energy food
Fowl Cholera		bacteria
Fowl pox		virus
Fowl Typhoid		bacteria
Gallid herpesvirus 1 or Infectious Laryngotracheitis		virus
Gapeworm	Syngamus trachea	worms
Infectious Bronchitis		virus
Infectious Bursal Disease	Gumboro	virus
Infectious Coryza		bacteria
Lymphoid leukosis		Avian leukosis virus
Marek's disease		virus
Moniliasis	Yeast Infection or Thrush	fungi
Mycoplasmas		bacteria-like organisms
Newcastle disease		virus
Necrotic Enteritis		bacteria
Omphalitis	Mushy chick disease	umbilical cord stump
Prolapse
Psittacosis		bacteria
Pullorum	Salmonella	bacteria
Scaly leg		parasites
Squamous cell carcinoma		cancer
Tibial dyschondroplasia		speed growing
Toxoplasmosis		protozoal parasite
Ulcerative Enteritis		bacteria

Chickens in agriculture

In the United States, chickens were raised primarily on family farms until roughly 1960. Originally, the primary value in poultry keeping was eggs, and meat was considered a byproduct of egg production.^[19] Its supply was less than the demand, and poultry was expensive. Except in hot weather, eggs can be shipped and stored without refrigeration for some time before going bad; this was important in the days before widespread refrigeration.

Farm flocks tended to be small because the hens largely fed themselves through foraging, with some supplementation of grain, scraps, and waste products from other farm ventures. Such feedstuffs were in limited supply, especially in the winter, and this tended to regulate the size of the farm flocks. Soon after poultry keeping gained the attention of agricultural researchers (around 1896), improvements in nutrition and management made poultry keeping more profitable and businesslike.

Prior to about 1910, chicken was served primarily on special occasions or Sunday dinner. Poultry was shipped live or killed, plucked, and packed on ice (but not eviscerated). The "whole, ready-to-cook broiler" wasn't popular until the Fifties, when end-to-end refrigeration and sanitary practices gave consumers more confidence. Before this, poultry were often cleaned by the neighborhood butcher, though cleaning poultry at home was a commonplace kitchen skill.

Two kinds of poultry were generally offered: broilers or "spring chickens," young male chickens, a byproduct of the egg industry, which were sold when still young and tender (generally under 3 pounds live weight); and "fowls" or "stewing hens," also a byproduct of the egg industry, which were old hens past their prime for laying.^[20] This is no longer practiced; modern meat chickens are a different breed. Egg-type chicken carcasses no longer appear in stores.

Battery chickens

The major milestone in 20th century poultry production was the discovery of Vitamin-D (named in 1922),^[21] which made it possible to keep chickens in confinement year-round. Before this, chickens did not thrive during the winter (due to lack of sunlight), and egg production, incubation, and meat production in the off-season were all very difficult, making poultry a seasonal and expensive proposition. Year-round production lowered costs, especially for broilers.

At the same time, egg production was increased by scientific breeding. After a few false starts, such as the Maine Experiment Station's failure at improving egg production,^[22] success was shown by Professor Dryden at the Oregon Experiment Station.^[23]

Improvements in production and quality were accompanied by lower labor requirements. In the Thirties through the early Fifties, 1,500 hens was considered to be a full-time job for a farm family. In the late Fifties, egg prices had fallen so dramatically that farmers typically tripled the number of hens they kept, putting three hens into what had been a single-bird cage or converting their floor-confinement houses from a single deck of roosts to triple-decker roosts. Not long after this, prices fell still further and large numbers of egg farmers left the business. This marked the beginning of the transition from family farms to larger, vertically integrated operations.

Robert Plamondon^[24] reports that the last family chicken farm in his part of Oregon, Rex Farms, had 30,000 layers and survived into the Nineties. But the standard laying house of the surviving operations is around 125,000 hens.

This fall in profitability was accompanied by a general fall in prices to the consumer, allowing poultry and eggs to lose their status as luxury foods.

The vertical integration of the egg and poultry industries was a late development, occurring after all the major technological changes had been in place for years (including the development of modern broiler rearing techniques, the adoption of the Cornish Cross broiler, the use of laying cages, etc.).

By the late Fifties, poultry production had changed dramatically. Large farms and packing plants could grow birds by the tens of thousands. Chickens could be sent to slaughterhouses for butchering and processing into prepackaged commercial products to be frozen or shipped fresh to markets or wholesalers. Meat-type chickens currently grow to market weight in six to seven weeks whereas only fifty years ago it took three times as long.^[25] This is due to genetic selection and nutritional modifications (and not the use of growth hormones, which are illegal for use in poultry in the US and many other countries). Once a meat consumed only occasionally, the common availability and lower cost has made chicken a common meat product within developed nations. Growing concerns over the cholesterol content of red meat in the 1980s and 1990s further resulted in increased consumption of chicken.

Today, eggs are produced on large egg ranches on which environmental parameters are controlled. Chickens are exposed to artificial light cycles to stimulate egg production year-round. In addition, it is a common practice to induce molting through manipulation of light and the amount of food they receive in order to further increase egg size and production.

On average, a chicken lays one egg a day for a number of days (a "clutch"), then does not lay for one or more days, then lays another clutch. Originally, the hen presumably laid one clutch, became broody, and incubated the eggs. Selective breeding over the centuries has produced hens that lay more eggs than they can hatch. Some of this progress was ancient, but most occurred after 1900. In 1900, average egg production was 83 eggs per hen per year. In 2000, it was well over 300.

In the United States, laying hens are butchered after their second egg laying season. In Europe, they are generally butchered after a single season. The laying period begins when the hen is about 18-20 weeks old (depending on breed and season). Males of the egg-type breeds have little commercial value at any age, and all those not used for breeding (roughly fifty percent of all egg-type chickens) are killed soon after hatching. Such "day-old chicks" are sometimes sold as food for captive and falconers birds of prey.^[26] The old hens also have little commercial value. Thus, the main sources of poultry meat a hundred years ago (spring chickens and stewing hens) have both been entirely supplanted by meat-type broiler chickens.

Traditionally, chicken production was distributed across the entire agricultural sector. In the twentieth century, it gradually moved closer to major cities to take advantage of lower shipping costs. This had the undesirable side effect of turning the chicken manure from a valuable fertilizer that could be used profitably on local farms to an unwanted byproduct. This trend may be reversing itself due to higher disposal costs on the one hand and higher fertilizer prices on the other, making farm regions attractive once more.

Chicken headcount in 2004

From the farmer's point of view, eggs used to be practically the same as currency, with general stores buying eggs for a stated price per dozen. Egg production peaks in the early spring, when farm expenses are high and income is low. On many farms, the flock was the most important source of income, though this was often not appreciated by the farmers, since the money arrived in many small payments. Eggs were a farm operation where even small children could make a valuable contribution.

Chickens as pets

Chickens can make good companion animals and can be tamed by hand feeding, but roosters can sometimes become aggressive. Some have advised against keeping them around very young children. Some people find chickens' behaviour entertaining and educational.

While some cities in the United States allow chickens as pets, the practice is not approved in all localities. Some communities ban only roosters, allowing the quieter hens. The so called "urban hen movement" harks back to the days when chicken keeping was much more common, and involves the keeping of small groups of hens in areas where they may not be expected, such as closely populated cities and suburban areas. City ordinances, zoning regulations or health boards may determine whether chickens may be kept.[5] A general requirement is that the birds be confined to the owner's property, not allowed to roam freely. There may be strictures on how far from human dwellings a coop may be located, etc.^[15]

Chickens are generally low-maintenance. The major challenge is protecting the birds from predators such as dogs, raccoons and foxes. A bird left out at night is likely to be killed by a predator. Chickens are usually kept in a roost at night and a pen in the day (unless they are free-range). The floor is covered with bedding such as straw or wood shavings, which, with the high-nitrogen droppings, can go into a compost pile.

Roosters are not required, as hens still lay eggs, but these eggs are not fertilized by the rooster therefore they will not hatch. Fresh egg yolks are "perky" and float above the white. Yolk color varies. According to Gail Damerow's handbook, "Egg yolks get their color from xanthophyll, a natural yellow-orange pigment in green plants and yellow corn, and the same pigment that colors the skin and shanks of yellow-skinned hens. The exact color of a yolk depends on the source of the xanthophyll." A subsequent table ascribes raw yolks colored "orange to dark yellow" to "green feed, yellow corn."^[16]

If hens are allowed to forage or are fed additional greens, their eggs may differ from USDA standards. Barb Gorski, a Pennsylvania farmer of pastured poultry, had some of her chicken eggs analyzed under the USDA-supported Sustainable Agriculture Research and Education (SARE) program. According to the laboratory results, "Eggs of the pastured chickens contained 34% less cholesterol, 10% less fat, 40% more vitamin A, twice as much omega-6 fatty acid, and four times as much omega-3 fatty acid as the USDA standard."^[17]

While the bulk of a pet chickens' diet should be a balanced commercial mix, for household chickens "green feed" can be as simple as poison-free, short grass clippings from lawn mowing. Chickens will forage for chickweed and other plants, seeds, and insects.

Chickens can also consume pulverized eggshells or otherwise unused food, such as meal leavings and old (but not rotted) produce. Damerow recommends leftover baked goods, fruit, or vegetable peelings, excess milk in modest amounts; advises against making such scraps the sole diet, or including raw potato peels "which chickens can't easily digest..." or "...anything spoiled or rotten...strong-tasting foods like onions, garlic, or fish."^[18]

In Asia, chickens with striking plumage have long been kept for ornamental purposes, including feather-footed varieties such as the Cochin from Vietnam, the Silkie from China, and the extremely long-tailed Phoenix from Japan. Asian ornamental varieties were imported into the United States and Great Britain in the late 1800s. Distinctive American varieties of chickens have been developed from these Asian breeds. Poultry fanciers began keeping these ornamental birds for exhibition, a practice that continues today. Individuals in rural communities commonly keep chickens for both ornamental and practical value.

Artificial incubation

Chicken egg incubation can successfully occur artificially as well. Nearly all fertilized Chicken eggs will hatch after 21 days of good conditions - 99.5 °F (37.5 °C) and around 55% relative humidity (increase to 70% in the last three days of incubation to help soften egg shell). Eggs must be turned regularly (usually three to eight times each week) during the first part of the incubation. If the eggs aren't turned, the embryo inside will stick to the shell and may hatch with physical defects. Some incubators turn the eggs automatically. This turning mimics the natural process – an incubating hen will stand up several times a day and shift the eggs around with her beak. However, if the egg is turned during the last week of incubation the chick may have difficulty settling in the correct hatching position.

Many commercial incubators are industrial-sized with shelves holding tens of thousands of eggs at a time, with rotation of the eggs a fully automated process. Home incubators are boxes holding from half a dozen to 75 eggs; they are usually electrically powered, but in the past some were heated with an oil or paraffin lamp.

An egg incubator.