Diseases Of Poultry, prevention and management


Diseases Of Poultry

Poultry can be affected by a variety of diseases and parasites. Disease of poultry include coryza, chronic respiratory disease,  infectious laryngotracheitis, lice and mite infestations, chlamydiosis, blackhead and internal parasites.A strict hygiene program is required to keep diseases out of poultry. Some diseases are controlled by vaccination or medication strategies.

There are four main types of disease affecting poultry: metabolic and nutritional diseases; infectious diseases; parasitic diseases; and behavioural diseases.

Metabolic and nutritional diseases Of Poultry

These are conditions caused by a disturbance of normal metabolic functions either through a genetic defect, inadequate or inappropriate nutrition or impaired nutrient utilisation. These include Fatty Liver Syndrome, Perosis (or slipped tendon), Rickets and Cage Layer Fatigue.

Infectious diseases Of Poultry

An infectious disease is any disease caused by invasion of a host by a pathogen which subsequently grows and multiplies in the body. Infectious diseases are often contagious, which means they can be spread directly or indirectly from one living thing to another. These include Avian Encephalomyelitis, Avian Influenza, Avian Tuberculosis, Chicken Anaemia Virus Infection (or CAV), Chlamydiosis, Egg Drop Syndrome (or EDS), Fowl Cholera (or Pasteurellosis), Fowl Pox, Infectious Bronchitis, Infectious Bursal Disease (or Gumboro), Infectious Coryza, Infectious Laryngotracheitis, Lymphoid Leukosis, Marek’s Disease, Mycoplasmosis, Necrotic Enteritis, Newcastle Disease and Salmonellosis.

Parasitic diseases Of Poultry

Parasitic diseases are infections or infestations with parasitic organisms. They are often contracted through contact with an intermediate vector, but may occur as the result of direct exposure. A parasite is an organism that lives in or on, and takes its nourishment from, another organism. A parasite cannot live independently. These include Coccidiosis, Cryptosporidiosis, Histomoniasis, Lice and Mites, Parasitic Worms (or Helminths), Toxoplasmosis and Trichomoniasis.

Behavioural diseases Of Poultry

Abnormal behavioural patterns can lead to injury or ill health of the abnormally behaving bird and/or its companions. These include Cannibalism (or aggressive pecking).

Common Diseases Of Poultry: –

Coccidiosis, New Castle disease, Fowl Typhoid and Fowl pox. Poultry also may suffer from ectoparasites and edoparasites in addition to other vices.


a. Causes

The disease is caused by coccidian, which multiply very rapidly in the intestines.  It usually occurs at 8 to 10 weeks of age and normally expresses itself in acute and chronic forms.  In the acute type, death occurs in 5 to 7 days.  The chronic type does not kill immediately but persists for long.

b. Symptoms

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.

c. Control

Sulphur drugs are normally used for treatment, use of coccidiostat in feed and always ensuring dry litter are other controls.

Fowl Cholera


a. Causes

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.

b. Symptoms

The disease spreads very rapidly in a flock.  There is yellowish colouration on birds’ droppings, which is followed by yellowish or greenish diarrhoea.  Infected birds become droopy, feverish and sleepy. The birds also sit with the head down or turned backwards or rested in feathers about the wing.

c. Control

Birds with acute type should be destroyed and burned. House should be thoroughly cleaned and disinfected.  Treatment with recommended sulphur drugs is effective.  Ensuring there is no wet litter is important, which provides ideal conditions for coccidian.

New Castle Disease

a. Causes

This disease is caused by a virus that infects respiratory and nervous system.  In both chicks and old birds mortality varies from 0 to 100% depending on virulence of the organism.

b. Symptoms

Egg production declines up to zero in 4 days. When laying resumes, misshapen eggs are produced with rough shells and sometimes bleached shells.

In chicks, gasping coughing and sneezing is observed and ater nervous systems.  Birds may be seen sitting on their back hock joints; others may walk backwards; or in circles; or hind their head between their legs.

In adult birds, external symptoms are more of respiratory nature, plus sudden decrease in egg production.  Birds lose appetite and are droopy.  If infection is severe, most birds sit on the floor and the roosts.

c. Control

Vaccinate chicks at 3 to 4 weeks of age. Repeat at 16 weeks of age and at the 24th week.  Thereafter vaccinate when there is an outbreak in the area.

Fowl Typhoid

a. Causes

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

b. Symptoms

Symptoms include dullness, ruffled feathers, paleness of the head drooping comb, loss of appetite and pale orange coloured diarrhoea. Symptoms appear in 3 to 4 day after infection and death occurs in 2 weeks.  The disease can be introduced into the flock by infected birds, materials, shoes, litter, etc.

c. Control

  • Vaccinate the birds at 7 weeks of age.
  • Destroy all dead birds by burning.
  • Do not allow visitors to enter into the poultry unit without being disinfected.

Pullurum Disease

a. Causes

Pullurum disease is caused by a microorganism called Salomonella Pullurum, 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.

b. Symptoms

Chicks utter squeaky chirps and appear drowsy and ruffle. Vent is sometimes smeared with faecal discharges. In adult birds no external symptoms are seen.  In baby chicks, symptoms are seen in 4 to 10 days with death occurring in 3 weeks.

c. Control

  • Destroy all confirmed carriers of the disease.
  • Clean and disinfect all the premises and incubators
  • Get chicks from hatcheries with good disease control programme.

Fowl Pox


a. Causes

Fowl Pox 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.


  • Provide footbath with disinfectant
  • Limit visitors to the unit
  • Workers should move from young to old flock in the units.
  • Clean and disinfect the house and equipment at the end of each crop and rest it for 1 to 2 weeks


These are mainly lice, fleas, mites and bedbugs.



These are roundworms, tapeworms, gapeworms, etc.


  • Provide proper sanitary conditions in the rearing units.
  • Treat the flock by using recommended drugs from veterinary.


Birds will develop abnormal behaviours such as cannibalism, breaking and eating eggs, etc.


  • Occupy the birds by supplying grass in the unit for them to pick on.
  • De-beak the birds if the problem continues.

prevention and management Diseases Of Poultry

Routine preventative measures form the next line of defence against disease, after providing a clean and hygienic environment through good poultry farming practices. Preventative measures include:

  • vaccination
  • parasite control
  • identifying and treating sick birds
  • separating multi-age flocks
  • practising routine biosecurity procedures between flocks and staff working with them.


Vaccination can prevent many poultry diseases. Follow a suitable vaccination program or only buy appropriately vaccinated stock. You can request vaccination certificates from your supplier when purchasing chicks or pullets.

Poultry vaccinations include:

  • avian encephalomyelitis
  • chicken anaemia
  • egg drop syndrome 76 (EDS 76)
  • fowl cholera
  • fowl pox
  • infectious bronchitis
  • infectious bursal disease
  • infectious coryza
  • infectious laryngotracheitis
  • Marek’s disease
  • Newcastle disease.

For breeders of poultry, when vaccinating:

  • always follow the instructions on the label, including storage conditions
  • use disposable syringes and needles
  • discard all unused vaccines, syringes and needles in a proper manner
  • be clean, but never use detergents or disinfectants near vaccination equipment. Do not disinfect skin before vaccinating with fowl pox or Marek’s HVT vaccine, as this will kill the vaccine virus.

Check with your vaccine supplier or veterinarian for vaccine availability. Poultry Hub has more information about vaccination types, procedures and handling.

Parasite control

Birds that are housed on the floor and have access to pastures and outdoor areas will have greater exposure to internal and external parasites. For birds housed in these conditions, it is important to have a prevention program in place and treat as required. This helps to minimise physical stress and keep birds in good condition so they can resist disease. Control parasites by:

  • regularly inspecting birds for external parasites
  • spraying or dusting birds thoroughly with an approved insecticide if you can see lice or mites – spray the shed, perches and nests thoroughly, making sure the insecticide gets into crevices
  • cleaning sheds and rotating ranges to prevent worms
  • regularly checking faecal material for any sign of worms
  • always checking the label on worming treatments for withholding periods as some are not suitable for production birds
  • consulting a veterinarian.

Remove sick birds

Regularly observe your birds for any signs of ill health or problems within the flock such as feather pecking. Remove sick chickens and other poultry from the main flock and obtain a diagnosis from a qualified person. Sick birds usually appear different to healthy birds. You can give the correct treatment once you identify the disease or problem. Keep ill birds quarantined from the flock until completely recovered. If medication is given, it is important to adhere to any withholding periods.

Multi-age flocks

When introducing younger birds into a flock of older birds, there is an increased risk of disease transfer from the older birds to the younger birds. Older birds often build resilience to diseases and disorders that younger birds have not been exposed to.

There may also be an increased risk of feather pecking and social issues when introducing new birds to a flock.

It is preferable from a disease perspective to run single-aged flocks. However if this is not possible and you are running multi-age flocks:

  • keep age groups separate – have an all-in and all-out system for each age group to allow for a complete clean and disinfection of facilities and equipment between batches
  • always start work with younger poultry and finish with the oldest.

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