List of Chicken Diseases: Symptoms and Treatment

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Poultry farmers often experience sudden death in chickens, and this is caused by diseases most times.

Viral diseases are more deadly, but bacterial infections can also cause death to birds in poultry.


Today, I’d talk about some of the major chicken diseases, their symptoms, prevention, and treatment.


While there are drugs for most poultry diseases, the most effective way of preventing poultry diseases is to improve your management practices.


Poultry Diseases Symptoms and Treatment

There are hundreds of chicken diseases and clinical symptoms, and ways to manage them.


Lymphoid leukosis

Lymphoid leukosis is a neoplastic poultry disease and it’s caused by the avian leukosis virus, hence, it’s also referred to as avian leukosis.

The avian leukosis virus transmission is mainly through eggs, but transmission at a young age may also occur in birds.

Lymphoid leukosis affects birds that are older than 25 weeks, and unfortunately, there is no treatment for this viral infection.

It’s important to note that lymphoid leukosis can not be transmitted to humans, but it’s contagious amongst birds.

What is Lymphoid leukosis

Lymphoid leukosis chicken symptoms

It causes cancer of internal organs such as the spleen, kidneys, liver, heart, and bursa of Fabricius.

Other Lymphoid leukosis chicken symptoms are the following

  • Slow growth rate
  • Lightweight
  • Listless, pale
  • A Drop in egg production in layers
  • The weakness of birds and eventually death.



The most effective way to prevent Lymphoid leukosis disease in your poultry is to purchase birds from hatcheries without a history of the disease.

The treatment of lymphoid leukosis in poultry may be almost impossible, therefore, good hygiene is important.


Mareks Disease

Mareks disease or paralysis is a common deadly poultry disease and it’s caused by the herpes virus.

The disease causes changes to the nerves and leads to paralysis and death after a few days.

chicken Mareks Disease

Marek’s Disease symptoms

Marek’s disease chicken’s symptoms are the following.

  • Loss of appetite
  • Reduced weight
  • Depression
  • Restlessness
  • Pale or/and shrunken combs

Paralysis is another clinical sign, and when this occurs, the chance of recovery is very low.

Paralysis makes the bird lying on its sides with one leg stretched forward and the other backward.


How to Prevent Marek’s disease in chickens

The best way to prevent Marek’s disease in chickens is to purchase birds from hatcheries without a history of the disease.

Good hygiene is also important, and once you notice, and confirm Marek’s disease, such bird should be destroyed and buried outside the farm.

Day-old chicks are infected through the oral and respiratory routes.

The disease starts manifesting at the point of lay, and you should vaccinate your birds at a day old.

Marek’s disease has no reliable treatment or vaccine but you can vaccinate your birds early to prevent the disease.


Egg Drop Syndrome (EDS) in layers

Egg drop syndrome is the production of soft shelled eggs or eggs without a shell, and also a reduction in egg production.

The egg drop syndrome can be fatal in layers. The causative virus is transmitted through the egg to a few birds in the flock.

These birds carry the virus until the flock comes into the lay at which time they begin to exercise the virus and infect the birds kept in the same house.


Symptoms of egg drop syndrome in chickens

  • The inability of layers to peak at a lay
  • Loss of appetite
  • Soft-shelled eggs

How to prevent Egg drop syndrome

You can only prevent egg drop syndrome by vaccination.


Egg drop syndrome vaccine

There is no egg drop syndrome treatment, but antibiotics and vitamins can be given to protect them from other infections.


Fowl Cholera

Fowl cholera is a bacterial and infectious disease caused by Pasteurella multocida.

Chickens of all ages can be affected by this avian disease.

Poultry birds may suddenly be found dead, even though they were previously looking healthy.

Fowl cholera management

Fowl cholera signs and symptoms

  • Loss of appetite
  • A drop in egg production
  • Weak and convulsion
  • Ocular, nasal, or oral discharge
  • Ruffled feathers
  • Greenish diarrhea
  • Wattles and combs may appear bluish


Fowl cholera Prevention

  1. Vaccination
  2. Strict hygiene
  3. Isolation of all infected birds

Management of Fowl cholera

Fowl cholera can be well controlled, especially with antibiotics such as penicillin, tetracycline, sulfadimethoxine, and erythromycin.


Chronic Respiratory Disease (C.R.D)

The causative agents of CRD are bacteria. Other predisposing factors may also contribute such as stress from debeaking, vaccination, and other harsh conditions such as extreme cold or poor ventilation.

Infected breeders can transmit the organism via the eggs to their offspring. Infection can also be through contact or airborne dust or droplets.

Chicken chronic respiratory disease

CRD signs and symptoms

  • Swollen face
  • Nasal discharge
  • Poor growth
  • A drop in egg production

The clinical signs and mortality are more severe in broilers than in layers.


Chicken Pullorum Disease

This disease is transmitted from a breeder through their eggs.

Infected chicks can also affect other chicks via droppings. The disease affects birds from 1 – 3 weeks’ old


Chicken Pullorum disease signs and symptoms

  • Chicks are seen huddled together as if they are feeling cold
  • Loss of appetite
  • Listless, ruffled, and droopy
  • Standing for a long time in one position
  • Whitish watery feces
  • Sudden death


How to Prevent chicken Pullorum disease

Strict hygiene

Isolate all infected birds

Avoid stress


Management of this disease

You can control chicken pullorum disease with antibiotics.


Fowl Typhoid

This is a disease in adult chickens and it is characterized by high morbidity and mortality. The disease can spread in a flock through infected droppings, dead birds carcasses, contaminated clothing, equipment, etc


Clinical signs of Fowl typhoid

  • Reduced feed intake
  • Listlessness
  • Evidence of intense thirst
  • Pale and shrunken combs and wattles
  • Yellowish diarrhea


How to Fowl typhoid

  1. Strict hygiene
  2. Isolate all infected birds
  3. Avoid stress


Treatment of Fowl typhoid

This disease can be treated with antibiotics


Infectious Coryza

This disease can spread within a flock through direct contact, airborne infected dust particles, and via drinking water, personnel, and equipment.


Signs and symptoms of Infectious Coryza

  • Sneezing and coughing
  • Respiratory distress
  • Swollen face and wattles
  • Foul-smelling discharge from nostrils and eyes
  • Drop-in feed and water intake
  • A drop-in feed and water intake
  • A drop in egg production

Infectious Coryza in chicken

How to prevent Infectious Coryza




Management of Infectious Coryza

Remove all infected birds promptly

Give sulfur drugs



This is a disease of economic importance in chicken production. Transmission between birds in a flock is mostly through infected droppings containing the oocysts of the coccidian.

It is mainly a disease in young chicks, but the outbreak has been reported in adult birds.

Affected birds may have white mucoid or bloody diarrhea, ruffled feathers, loss of weight, etc.


Symptoms of Coccidiosis

  • Hunched back
  • A dropping of wings
  • Birds appear sleepy
  • loss of appetite
  • A drop in egg production
  • Bloodstained droppings


Prevention of Coccidiosis

  • Good litter management
  • Strict hygiene
  • Vaccination
  • use coccidiostat in feed or water


Management of Coccidiosis

Sulpha drugs




There are four different types of helminths (worms) that are of economic importance in chickens. They are

  1. Tapeworms
  2. Roundworm
  3. Threadworms
  4. Caecal worms


Clinical signs of Helminthiasis

Tapeworm seldom causes serious damage except that they deprive the host chicken of nutrients, but the larvae form of the roundworm and capillaries can cause the destruction of the intestinal lining which may lead to enteritis, anemia, drop in egg production, and in some cases pale yolked eggs, generally referred to as platinum yolks.


Prevention of Helminthiasis

Good litter management

Routine deworming


Management of Helminthiasis

Use appropriate dewormer.


Lice Infestation

Lousiness is a common consequence of poor management and overcrowding.


Clinical signs of Lice Infestation

  • Discomfort
  • Loss of blood from frequent sucking of the lice

Prevention of Lice Infestation

  • Delouse
  • Avoid crevices on the walls





Mites infestation

Two types of mites are of economic importance in chicken. They are-

Depluming mites

Red mites


Clinical signs of Mites infestation

They are found at the base of the feathers leading to feather loss and restlessness

  • Irritations
  • Reduced feed consumption
  • A drop in egg production
  • Prevention
  • Good hygiene



Use Acaricides


Malabsorption Syndrome

This is a disease common with broilers and is caused by viral and bacterial agents.

The causative agents primarily attack the digestive which may manifest as nutritional deficiency lesions.

This disease has variously been referred to as helicopter disease, femoral head Necrosis, Brittle bone disease, infectious Proventriculitis, Pale bird syndrome, Runting disease, and stunting disease.


Clinical signs of Malabsorption Syndrome

  • Early diarrhea in chicks from 2 weeks of life
  • Light or dark brown foamy droppings with traces of undigested food particles
  • Mal-positioned wing feathers
  • Rickets and femoral head necrosis
  • Growth retardation


Management of Malabsorption Syndrome

All affected birds should be culled

Dietary supplementation of feed with vitamin E and Selenium could offer some palliative assistance

Strict hygiene



Young chicks of 2-5 weeks are commonly affected


Clinical signs of Rickets

The weakness of the legs, claws, and beak

Soft-shelled eggs in layers


Prevention of Rickets

Provide well-balanced feed with adequate minerals (calcium, Phosphorus) and Vitamin D


Vitamin Deficiency

In young chicks, Vitamin B2 deficiency may be seen leading to their inability to walk.


Clinical signs of Vitamin Deficiency

  • Drowsy, in-coordination
  • Poor feathering
  • Fall in egg production
  • Reduced hatchability
  • Convulsion
  • Backward retraction of the head
  • Death


Prevention of Vitamin Deficiency

Multivitamin supplementation


Management of Vitamin Deficiency in chicken

If the disease has not caused irreversible damages, give appropriate supplementations.


Infectious Synovitis

This disease can be transmitted from the infected breeder to its offspring through eggs. Other means of contact are through the chicken to chicken contact, personnel, clothing, and equipment.


Clinical signs of Infectious Synovitis

  • Weight loss
  • Inability to walk
  • Swollen hock joint and feet which are hot to touch


Prevention of Infectious Synovitis

Good litter management

Hatching eggs should be dipped before setting


Management of Infectious Synovitis

Give antibiotics


Thrush or Moniliasis or Sour crop disease

This is a mycotic disease of the digestive tract of chickens caused by candida Albicans.

Young chicks are more susceptible and malabsorption of feed occurs following administration of therapeutic levels of various antibiotics.


Clinical signs of Thrush

  • Stunted growth
  • Listlessness
  • Ruffled feathers
  • Foul-smelling discharge from the mouth
  • Loss of appetite and weight


Prevention of the disease

Good hygiene

Avoid overcrowding



Remove affected birds

Give copper sulfate in drinking water


Spirochaetosis (Tick fever)

It is caused by a bacterium Borrelia anserine and infection is by ingestion of contaminated feces, feeds, fowl ticks, etc.

Birds of all ages are susceptible but older birds are more resistant and may receive spontaneously.


Clinical signs of Spirochaetosis

  • Increased body temperature
  • Darkened head part
  • Increase in thirst
  • yellowish-green diarrhea
  • Combs and wattles are pale
  • High mortality


Prevention of Spirochaetosis

  • Avoid thick infestations
  • Management
  • Destroy ticks with acaricides
  • Apply arsenicals and antibiotics



This is a fungal disease of chickens. Transmission is primarily through inhalation of fungal spores from contaminated litter like wood shavings it contaminated feed.


Clinical signs of Aspergillosis

Depressed breathing, gasping, and coughing


Prevention of Aspergillosis

Strict hygiene in breeder and hatchery

High-quality fungal spore-free wood shavings should be used


Management of Aspergillosis

Affected birds should be culled and destroyed

Miscellaneous Abnormalities


Prolapsed of the oviduct

This is the version of the oviduct and rectum through the vent to the extent that it cannot go in again.

Affected birds should be slaughtered. Faulty feeding leading to over-fatness, unregulated lightening programs and early introduction of pullets to layers diet can lead to this abnormality.

Hormonal imbalances, extra-large eggs, physical injuries to the oviduct such as pecking of the vent, and severe worm infestation can also cause the prolapse of the oviduct.