Disease and Pest Control

USDA Defend the Flock Program

If a poultry producer is to reap all the benefits from the investment of money, time and labor, he must maintain a healthy and parasite-free flock. The health status of his birds is important to the producer whether he maintains a backyard flock or commercial poultry flock. Constant monitoring of the flock is the first step in detecting diseases. Identification of the cause and appropriate treatment can prevent a minor condition from becoming an unprofitable enterprise.

The discussions within the following questions and references will aid in maintaining a disease-free, healthy flock that will be a pride to the owner.

Frequently Asked Questions

My chickens have dark warts and sores on their face, wattles and combs, what's wrong?
Warty Growths on Comb - The appearance of warty growths or sores on the fleshy parts of a chicken's head is not usually a health risk that the producer should be concerned with. These lesions are produced as the bird's response to fowl pox virus injected by a mosquito. The condition appears more serious than it actually is. A scab forms as the bird develops a resistance to the viral disease organism. The bird will not usually show other effects to the disease and will recover within a short time unless complications arise.

A more detailed discussion of fowl pox is included in Diseases of Poultry.

Why are the shanks or legs of my chickens rough and scaly?
Scaly-Leg Mites - The producer will often observe shanks or legs of birds that have scales that seem to protrude straight out from the leg. This problem is caused by small scaly-leg mites that bury under each scale and cause an irritation of the skin and the production of cells and substances that try to "wall-off" these mite parasites. Most free roaming chickens will have infestations of these mites but they seldom cause problems other than creating an irritation to the birds.

Effective treatments of the condition include weekly coating of the birds' legs with petroleum-based or mineral oils that suffocate and kill the mites. Alternative treatments include the use of approved pesticides like permethrin. All birds in the flock should be treated to reduce reinfestation from untreated birds.

A more detailed discussion of the scaly-leg mite is included in Diseases of Poultry.

Why do my birds have an absence of feathers on parts of their bodies?
The absence of feathers on birds can result from any of several causes and can be separated into two groups: 1) those birds that cannot grow feathers and 2) those birds that pull or break them off. Either situation can be reversed by correcting the problem's cause.

The most common reason that feathers do not develop is a deficiency of a critical protein constituent (amino acid) from the diet of the birds. The feathers of birds contain high levels of a subunit of proteins called "methionine." Methionine is one of only a few amino acids that contain sulfur, and sulfur is a major constituent of feathers. If bird diets are deficient in any single amino acid, it will most likely be methionine. An adequate level of methionine is required in the diet and a deficiency results in reduced growth and feather development. A methionine deficient bird will tend to eat feathers in an attempt to satisfy a craving for this amino acid. A bird may even pull them from its own body.

Few ingredients used in making poultry diets contain adequate amounts of methionine, so manufactured methionine must be added to the dietary mixture to ensure that the birds receive an adequate amount. All quality poultry feeds are designed to contain adequate methionine and prevent reduced body growth and feather development. However, if additional grains (such as corn) are fed with the complete feed, then the amount of methionine consumed by the bird can be inadequate for providing growth and feather development. Feeding of additional grains with complete poultry feeds is not recommended.

If feathers are developed, but are pulled or broken off, the cause is usually management related. Birds that frequently mate may have an absence of feathers, especially on the backs and heads of hens. The males may also have feathers missing from the breast area. These feathers will grow back after the breeding season is completed. Consult the publication Solutions for Poultry for recommendations for the supplementation of methionine when feeding methionine deficient diets.

If feathers are missing from the abdominal and vent area, the cause is most likely the presence of external parasites such as the northern fowl mite or poultry lice. Infestations of these pests can be controlled by regular sprayings of an approved pesticide like permethrin to the birds. The house and other structures that the birds frequently visit should also be sprayed. This will ensure the elimination of any pests that can reinfest the birds. Several applications at 2 to 3 week intervals will kill pests that hatch from eggs that have been deposited prior to the initial spraying. Consult the publication External Parasite Treatments for approved treatments used on poultry.

My bobwhite quail appear sick and are losing weight (especially in breast muscles) and the mortality is very high. What is wrong?
Ulcerative Enteritis in Quail - Often quail will lose weight and muscling of the breast before they die. The condition usually exists in various stages within the entire population of birds. The breast bone will lack any muscle covering and seems to be covered only by a layer of skin. The name of the condition is Ulcerative Enteritis, or Quail Disease.

The disease is caused by a bacterial infection in the small intestine of the bird. Ulcers appear and reduce the amount of nutrients that the intestine can absorb. The lack of nutrients causes the extreme weight loss and muscle deterioration.

More information on this disease is available in the Diseases of Poultry publication. It is generally recommended that a preventative drug like bacitracin or penicillin be included in the feed to reduce the incidence of outbreaks. Use of a coccidiostat like monensin has also shown to be beneficial.

Many strains of the disease causing bacteria have been isolated and some strains have shown high resistance to the more beneficial drugs we use. Good management practices will help reduce the severity of these outbreaks. These practices include:

• Keep water troughs clean or use nipple waterers.
• Do not let visitors into the bird producing areas.
• Clean and disinfect all equipment before taking it near the birds.
• Do not bring any new birds onto the premises. If you need to increase flock size, hatch chicks from purchased eggs or eggs you produce.
• Addition of 6-10 lb salt to each 100 square feet of litter or growing area has been reported to reduce ulcerative enteritis outbreaks.
• Maintain a good insect pest and rodent control program to reduce disease spread.
• Wear clean clothes and disinfect footwear before entering quail rearing facilities.

The key point to remember about this disease is that most disease outbreaks are spread by the bird caretaker, not by the birds. Precautions you take to prevent the disease from entering the premises will be much more rewarding than trying to "treat" yourself out of a disease problem.

How do I treat my chickens to remove intestinal worms?
Internal Poultry Parasites

Internal parasites can severely reduce the productivity of poultry and cause mortality in the most severe cases. Poultry are infected by a number of internal parasites. A description of each parasite and its treatment can be found by linking to the appropriate internal pest shown below.

Ascaridia (poultry intestinal roundworms
Cecal Worms
Capillary Worms
Tapeworms
Gapeworms

See Diseases of Poultry section for more information.

How do I treat birds to kill mites and lice?
Treatments for External Poultry Parasites - External parasites on poultry are a common problem in small flocks of birds. They often come in contact with the parasites or their eggs while foraging for food. The problems are less frequently encountered in commercial poultry flocks but treatments may also need implementing in these flocks. Several pesticides provide excellent protection against parasites. The product used and the method of administration is dependent on the parasite and type of housing conditions being used. A description of the most commonly encountered parasites can be found in the parasite section of Diseases of Poultry. A listing of the most effective pesticides are shown in Pesticides Used for Control of Poultry Insect Pests.