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Diseases & Medications


University of Connecticut Cooperative Extention System - College of Agriculture and Natural Resources [16.5KB]

Fact Sheet -

Poultry Diseases & Medications For Small Flocks

AVIAN INFLUENZA - (See Fact Sheet for this disease)

Reportable, contagious, and high mortality disease of both domestic and wild birds.
Transmitted by people, birds, flies, and egg flats and egg cases.
Signs are coughing, sneezing, and sudden deaths.

COCCIDIOSIS - Very common disease.

Pale birds; bloody droppings; ruffled feathers; deaths.
One celled parasite - coccidia - 9 species.
Host specific; immunity specific.
Coccidia - need moisture, O2, and temperature.
Prevent by keeping birds dry; feed 0.0125% Amprol continuously to 8 weeks of age.
Amprol @ 1/3 oz. Powder/gallon water 10-14 days for treatment.

ROUNDWORMS - Very common. Larger worms.

Damage by blocked intestine; excrete toxin.
Decreased egg production; direct life cycle - 28 days.
Piperazine for 12-24 hours - 50mg/lb body weight.
Meldane feed 18-21 days.

CAPILLARIA WORMS - Common. Small hairworm.

Decreased egg production; pale yolks; poor hatchability.
Add extra Vitamin A - 12,000 I.U. / pound feed 3 weeks.
Meldane feed 18-21 days.

LICE, MITES - Common parasites of skin and feathers.

Cause anemia due to loss of blood.
Decrease egg production and can produce mortality.
Dust or spray with Sevin.
Must hand dust the males. Females will dust themselves.

MAREK'S DISEASE - Cancer of the chicken; NOT contagious to humans.

Cause tumors in nerves (paralysis), in liver, ovaries, testicles, muscles and skin - sudden death.
Mortality can go to 20%.
No treatment; prevention by day old vaccination at hatchery.

RESPIRATORY DISEASES - Very common in Connecticut.

Infectious Bronchitis - Sneezing, decrease in egg production and egg shell quality.

Newcastle Disease - Sneezing, decrease in egg production and internal egg quality.

Infectious Laryngotracheitis - Sneezing, coughing, choking, high losses.

Pox - Cause respiratory signs if pox lesions in mouth, throat, and windpipe; skin lesions on comb and face.

MEDICATIONS - Most commonly used.

Terramycin (Oxytetracycline) - safe; use @ 200 mg. To 1000 mg. (1 Gm.) per gallon water; withdrawal time - 5 days.

Aureomycin (Chlortetracycline) - use exactly as Terramycin.

NF 180 - not water soluble - must use in feed @ 100-200 Gm./ton.

Neomycin - good against E. coli bacteria. May use in water or feed.

Gallimycin (Erythromycin) - water or feed, good against Mycoplasma. Withdrawal - 1 day.

Amprolium (Corid) - for treating coccidiosis; very safe. (See recommended dose under coccidiosis).

Sulfaquinoxaline or Sulfamethazine - water or feed; less safe; somewhat toxic to bone marrow. Withdrawal - 10 days.

Tramizol - wormer, 20 mg. Per bird per day (1 Gm. powder per gallon water for 1-2 days).


Rickets - Deficiency of Vitamin D3, calcium and/or phosphorus. Add cod liver oil and DiCal or steamed bone meal.

Vitamin E deficiency - Crazy chick disease. Add source of pure Vitamin E.

Curly Toe Paralysis - Deficiency of riboflavin. Add milk products.

Perosis or slipped tendon - Deficiency of choline, manganese, biotin. Add choline, manganese, and/or biotin.

Vitamin A deficiency - Pale birds. Add cod liver oil.

Small Flock Vaccination Schedule for Replacement Pullets

This schedule is designed to protect small or backyard flocks or poultry kept for egg production from common respiratory diseases of poultry that may occur in Connecticut. We do not recommend vaccinating meat birds.

A vaccine administered through the drinking water is recommended. Watering equipment should be free of disinfectant including chlorine and city water or the vaccine will be destroyed. Remove water up to 2 hours in hot weather and 2-4 hours in cool weather before administering.

Follow manufacturer's directions for storage and use.

In a clean container, mix one half teaspoon of powdered skim milk per quart of water. This will neutralize small amounts of sanitizer and keep the virus in the vaccine alive and potent much longer.


2 weeks
Newcastle Disease Hitchnet B-1 ("B-1 Type -B-1 Strain")
Infectious Bronchitis Massachusetts-Connecticut Strain
in water
7 weeks Newcastle Disease Lasota (B-1 Type Lasota)
Infectious Bronchitis (Hollan Mild Strain)
in water
12 weeks Infections Laryngotracheitis in water
15 weeks Newcastle Disease Lasota (B-1 Type Lasota)
Infectious Bronchitis (Regular Holland Strain)
in water
18 weeks Pigeon Pox (only for show birds) wing web


Worms can sometimes be found in the intestines of chickens. When chickens are kept on a litter floor, the worms will have direct cycle through their droppings. Worm eggs are discharged in the droppings; after the worm eggs incubate in the litter for about 10 days they will contain larvae, and other chickens will pick up these embryonating worm eggs and become infected with worms.

Two major kinds of worm exist:

1. Roundworms (Ascaridia galli)

These are large worms up to 3 inches long that can live in the intestine, use the chicken's nutrients while the larvae damage the intestinal wall. Piperazine, a common harmless wormer, will eliminate roundworms, but reinfection of the chickens can occur through the litter. Piperazine should be given in the drinking water twice, with a 3-week interval.

Roundworms can cause drops in egg production, but normally do not harm the birds severely. However, intestinal absorption of nutrients will be interfered with.

2. Hairworms (Capillaria).

These worms are much smaller than roundworms, approximately 1/2-inch in length and very thin threadlike. Therefore they are difficult to find in the intestinal contents. Capillaria have a direct litter bird cycle or an indirect cycle via earthworms, the latter being a factor in chickens that range outdoors. Capillaria cause considerable damage to the intestinal wall and can deprive the chicken of nutrients and vitamins.
Platinum yolks can be found in eggs from infected hens as well as paleness of the birds themselves.
Treatment with piperazine does not eliminate capillaria, and other wormers will have to be used. The feed is often supplemented with extra vitamin A in capillaria-infected chickens.

In addition to these two commonly occurring worms in chickens, we can find other kinds that are of lesser importance:

3. Cecal worms (Heterakis)

These are worms that inhabit the ceca (blind sacs in intestine), but do not appear to cause sickness in chickens.

4. Tapeworms

Tapeworms are occasionally found in chickens. They require special treatment, but usually do not constitute a hazard to the chicken's health, unless large numbers are present.

5. Gapeworms

Gameworms occupy the trachea of pheasants primarily, but may be found in chickens, too. Cause gasping in pheasants and young chickens. Special wormer is required for gapeworms. Gapeworms cycle through earthworms, so chickens will get infected only outdoors or on dirt floors.

In an average chicken flock with floor operation, good management practices and periodical piperazine or other worm treatment when roundworms or hairworms are present will keep the flock healthy. If severe worm problems exist, a good worming program should be instituted, for which advice can be obtained from the Extension Service. Wire floors eliminate the worm cycle and keep chickens free of intestinal worms.


Coccidiosis is one of the oldest and most widely known diseases of poultry, Although there are good effective treatments and preventive medications (coccidiostats) for coccidiosis, it still occurs quite frequently in chickens today.

Coccidiosis is a disease caused by the invasion of the intestinal wall with coccidia, a type of microscopic one-cellular animals caused protozoa.

There are basically nine kinds of coccidiosis in chickens. One kind: Eimeria tenella, causes cecal coccidiosis, where blood is found in the two blind pouches (ceca) of the chicken-gut, and in chronic or healed cases a yellow core ("cigar") can be found in the ceca. The other eight kinds infect the small intestine. The two most important ones are Eimeria Acervulina and Eimeria Necatrix. Both damage the intestine severely and can cause morality, unthriftiness and loss of egg-production. Turkeys have their own kinds of coccidiosis, different from chicken varieties. There are seven species of coccidiosis found in turkeys.

A mild coccidiosis infection is not very harmful and is actually necessary to create immunity in the future laying hen, if she is to live on the floor.

Coccidiosis organisms develop little eggs (oocysts) in the intestine that are passed in the droppings and can then infect other chickens in the same pen. If chickens are held on wire floor, they cannot get in contact with droppings and will generally remain free of coccidiosis. Wet litter and warm temperature induce a heavy coccidiosis infection in the litter. That's why many coccidiosis outbreaks occur in the springtime (May, June).

Preventively, drugs are given in the chicks starter and grower feed, from day-old until 12-15 weeks of age. Such drugs are called coccidiostats, because they inhibit the growth of the coccia, but leave enough coccidia alive to permit the build-up of immunity to coccidiosis in the growing pullet.

In broilers, no immunity against coccidiosis is needed because of their short life span. Therefore in broilers we frequently use coccidiostats that completely inhibit coccida build up.

Severe infections of coccidiosis will result in young chickens being sleepy and sitting with ruffled feathers. In cases of cecal coccidiosis, dropping will contain blood. Heavy mortality can result if treatment is not started immediately.

Treatment consists of drugs such as liquid amprolium or sulfa drugs (Sulmet, ESB3 or Whitsyn), but one should be careful with sulfa drugs, as they can be toxic when given too long or in too high dosages. Never give sulfa drugs to laying hens. In E. Necatrix infectious blood may occur in the intestine and mortality can be 1% per week or more.

E. Acervulina infections are less dramatic, but tend to be more chronic in nature with long term damage to the intestine and resulting in smaller, unthrifty pullets that do not produce enough eggs.

If chickens appear sick and ruffled from coccidiosis, get a diagnosis at a diagnostic laboratory. It can be made quickly and medication started immediately.