Diseases of Chickens

Disease refers to any alteration in the state of an animal’s body, or the abnormal functioning of an organism’s body. Chicken diseases are primarily classified by their cause:

• Bacterial diseases: e.g., Fowl Typhoid, Fowl Cholera
• Viral diseases: e.g., Fowl Pox, Newcastle, Gumboro
• Protozoan diseases: e.g., Coccidiosis

1. Newcastle Disease

• Cause: Virus
• Modes of Transmission: Direct contact with infected chickens.
• Signs and Symptoms: Paralysis of one side, loss of balance, twisting of the neck, difficulty breathing, green diarrhea, shaking.
• Prevention and Control:
  • Vaccinate chickens at 3 weeks old.
  • Cull (kill and burn or bury) all infected chickens immediately.
  • Maintain strict sanitation and hygiene in the chicken house and with utensils.
  • Never mix old chickens with newly bought ones.
  • Ensure adequate ventilation in the chicken house.

2. Fowl Pox

• Cause: Virus
• Modes of Transmission: Contact with infected chickens.
• Signs and Symptoms: Sores on the comb, wattles, and around the beak.
• Prevention and Control:
  • Vaccinate chickens at 3 weeks old.
  • Treat existing sores with an iodine solution.
  • Isolate sick chickens from healthy ones.

3. Gumboro Disease (Infectious Bursal Disease – IBD)

• Cause: Virus
• Modes of Transmission: Direct contact with infected chickens.
• Signs and Symptoms: Dullness, sleepiness, swollen cloaca, restlessness, and high mortality rates, particularly in 4-week-old chicks.
• Prevention and Control:
  • Vaccination.
  • Prophylactic treatment using antibiotics (to prevent secondary bacterial infections).

4. Coccidiosis

• Cause: Protozoa called Coccidian.
• Modes of Transmission: Ingesting coccidia from contaminated ground, feed, or water.
• Signs and Symptoms: Blood-tinged feces, rough plumage, and death of chicks.
• Prevention and Control:
  • Vaccination.
  • Keep the chicken house dry to reduce the multiplication of coccidia.
  • Administer amprolium in water or feed.

5. Fowl Typhoid

• Cause: Bacteria.
• Modes of Transmission: Trans-ovarian (from hen to egg), direct contact, contaminated feed, water, or environment. It’s important to note that consuming raw infected eggs can be dangerous to humans.
• Signs and Symptoms: Whitish-yellowish or green-yellowish diarrhea, difficulties in breathing, dullness, drooping wings, sleepy eyes, anemia (comb and wattles become shrunken and pale yellow). Sudden death is common.
• Prevention and Control:
  • There is often a poor response to treatment once infected.
  • Test and cull (kill) infected birds.
  • Regular vaccination.
  • Keep poultry houses clean, dry, and well-ventilated.

6. Fowl Cholera

• Cause: Bacteria.
• Modes of Transmission: Contact with carriers, contaminated feeds and water, contaminated soil or litter, and improperly disposed infected carcasses.
• Signs and Symptoms: Inappetence (loss of appetite), loss of body weight, gasping, coughing, sneezing, difficulties in breathing, diarrhea with grey-yellow/green color, lameness and swelling of joints (wings and legs), head, comb, and wattles turning purple, and edema (swelling) around the eye region.
• Prevention and Control:
  • Keep new birds in isolation for one month before mixing them with existing flocks.
  • Never mix old birds with young ones.
  • Slaughter all sick birds immediately.
  • Disinfect the house thoroughly before introducing new birds.
  • Vaccinate chickens when they are 8-12 weeks old.
  • While drugs like sulphadimidine can be effective, economic treatment for an outbreak is often challenging.

Parasites of Chickens

Parasites are organisms that live and feed on other living organisms (hosts), causing harm.

• External Parasites: Feed on the external parts of a host (e.g., lice, mites, tampans, fleas).
• Internal Parasites: Live inside the host animal (e.g., roundworms, hookworms, tapeworms).

1. Mites

• Effects: Suck blood, causing anemia, general body weakness, irritation, and discomfort.
• Control:
  • Burn litter and nesting boxes to control infection.
  • Fill cracks in the coop, which are common hiding places for mites.
  • Clean the house, feed, and water troughs thoroughly.
  • Disinfect the house and equipment.

2. Tapeworms

• Effects: Suck food nutrients from the small intestines, leading to retarded growth in chicks and loss of egg production in layers. They also increase susceptibility to other diseases, cause diarrhea, and increased thirst.
• Control:
  • Ensure high standards of sanitation and hygiene.
  • Provide chicks with clean water.
  • Confine chicks to prevent them from ingesting intermediate hosts like ants and grasshoppers.
  • Pasture dressing with benzene hexachloride can be used.
  • Treatment is generally not economical; however, di-n-butyl tin dilaurate or di-n-butyl tin oxide can be effective.

3. Roundworms

• Effects: Suck food nutrients from the small intestines, causing retarded growth, reduced egg production, diarrhea, hemorrhages, and anemia.
• Control:
  • Keep the chicken house clean.
  • Always keep water and food troughs clean.
  • Do not put old and young chicks together.
  • Administer deworming drugs like piperazine, phenothiazine, or hygromycin.

4. Fleas, Tampans, and Lice

• Effects: Cause body irritation, suck blood leading to irritation and anemia. Heavy infestation of the head by tampans can cause swelling and ulcers.
• Control:
  • For fleas, apply lard with paraffin to infected areas to suffocate them.
  • Remove and burn infected litter.
  • Apply malathion or creosote to the infected house.

5. Hookworms

• Effects: Attach to the intestinal lining and suck blood, causing anemia, leading to weight loss and weakness.
• Control:
  • Disinfect the chicken house.
  • Use a foot bath with disinfectants at the entrance to the chicken house.
  • Ensure proper disposal of chicken droppings.

General Effects of Parasites on Chickens

• Damage the skin of animals.
• Suck blood and cause anemia.
• Act as vectors for some diseases.
• Cause irritation and discomfort.
• Feed on body tissues, causing anemia and retarded growth.
• Can block the digestive system of animals.

Chicken Predators

Predators are animals that catch and feed on farm animals, such as chickens. Common chicken predators include:

• Wild cats
• Hawks
• Eagles
• Ravens
• Alligators
• Nyenga
• Snakes

Ways of Controlling Predators

• Raise chickens under the intensive system, e.g., in battery cages or fully enclosed coops.
• Keep the chicken house well-lighted so the farmer can easily spot any predators.
• Ensure vents are fitted with wire mesh to prevent snakes and cats from entering.
• Construct the chicken house with strong, durable materials.
• Keep guard dogs that are trained to protect poultry.
• Construct a strong fence around the chicken house.
• Use baited traps to catch specific predators.
• Install bright security lights at night to deter nocturnal predators.