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Common diseases that affect poultry and their symptoms

By Alex Wachira

For maximum production and rewards, poultry must be kept healthy. Peter Maina looks at his kienyeji chicken. [Duncan Ocholla, Standard]


Poultry farming is one of the most popular in Kenya which earns farmers’ great income and returns from the sale of eggs, meat, and feathers.

Animal waste or manure obtained from the birds is used on the farms to boost soil fertility or sold to other farmers.

For maximum production and rewards, poultry must be kept healthy.

Common diseases known to affect poultry as listed by in Kenya include:

1. New Castle Disease

It is caused by a highly contagious virus that infects the respiratory and nervous system.  In both chicks and old birds’ mortality varies from zero to 100 percent depending on the virulence of the organism.

The disease is spread to chicken by direct contact with droppings or discharges from infected birds. 

It affects all poultry including chicken, ducks, turkeys, pigeons but chicken are the most affected.

Symptoms include:

Egg production declining up to zero in four days. When laying resumes, misshapen eggs are produced with rough and sometimes bleached shells.

In chicks, gasping coughing and sneezing is observed, nasal discharge, depression, and diarrhea. 

Birds may be seen sitting on their back hock joints; others may walk backward, or in circles; or hide their head between their legs.

In adult birds, external symptoms are more of respiratory nature and sudden decrease in egg production.

 Birds lose appetite and are droopy. 

If the infection is severe, most birds sit on the floor and the roosts.

In severe illness, other symptoms include swelling of the head, twisted neck, and leg paralysis. 

2. Gumboro/infectious bursal disease

It is a highly contagious viral disease that affects poultry but mainly chickens particularly at three to eight weeks old.

The chicken gets infection directly on contact with infected birds or indirectly through contact with material contaminated with infected fecal matter.

Contaminated clothes, beddings, equipment, and other materials can spread the disease to a flock. The virus causing this disease is stable in the environment and particularly difficult to eradicate once it infects a flock.

Symptoms include severe prostration, watery whitish diarrhea, soiled vent feathers, inflammation of the cloaca and eventually death.

3. Fowl Typhoid

The disease is caused by a microorganism called salmonella gallinarum or shigella gallinarum.

Symptoms include dullness, ruffled feathers, paleness of the head drooping comb, loss of appetite and pale orange coloured diarrhea.

Symptoms appear in three to four days after infection and death occur in two weeks.  The disease can be introduced into the flock by infected birds, materials, shoes, litter, etc.

4. Fowl Cholera

The disease is caused by pasteurella avicida, a microorganism that multiplies very rapidly in the blood causing poisoning. 

Sick birds, wild birds, human, animals or utensils transmit the disease.

Symptoms include a yellowish colouration on birds’ droppings, which is followed by yellowish or greenish diarrhea.  Infected birds become droopy, feverish and sleepy.

The birds also sit with the head down or turned backward or rested in feathers around the wing.

The disease spreads very rapidly in a flock. 

5. Pullorum Disease

Pullorum disease is caused by a microorganism called Salmonella Pullorum, which infects the ovary of the hen.  The microorganism can also be found in the intestine of chicks. 

The disease is usually spread by eggs laid by birds carrying the microorganism and chicks hatched from those eggs.


Chicks utter squeaky chirps and appear drowsy and ruffle. The vent is sometimes smeared with fecal discharges.

In adult birds, no external symptoms are seen.

In chicks, symptoms are seen in four to 10 days with death occurring in three weeks.

6. Fowl Pox

Fowlpox is a highly infectious skin disease. It is characterized by typical pox lesions in the form of wart-like scabs on the face, comb, and wattles. It causes painful sores on the featherless skin and/or the respiratory and digestive tract.

Chicken are infected through contact with scabs from infected birds or through blood-sucking insects such as mosquitoes.

Symptoms include:

Blisters which enlarge into painful yellow bumps and finally to dark coloured wart-looking scabs in the skin in non-feathered areas such as comb, wattle, face, and eyelids.

Difficulty in breathing and eating due to diseases affecting the respiratory system, mouth, and throat.

7. Coccidiosis.

The disease is caused by coccidian, which multiplies very rapidly in the intestines.  It usually occurs at eight to 10 weeks of age and normally expresses itself in acute and chronic forms.  In the acute type, death occurs in five to seven days.  The chronic type does not kill immediately but persists for long.


Infected birds or chicks become droopy, look unthrifty, and usually have ruffled feathers, pale beaks, and shanks.

Caecal coccidiosis has bloody droppings. 

Mortality may be high and sudden.

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