Respiratory diseases in chickens

M.S.K. Mashishi 

What are respiratory diseases?

Respiratory diseases affect the sinuses (an area in the head between the eyes and the beak) as well as the windpipe and lungs

What are the causes?

What are the signs in live chickens?

What are the signs in dead chickens?

         The nasal passage and windpipe may be red on the inside or filled with mucous

How do you confirm the disease?

What is the treatment?

Prevention and control

Respiratory diseases caused by viruses

Newcastle disease (NCD)

Infectious bronchitis (IB)

Infectious laryngotracheitis (ILT)



These are viral diseases causing respiratory signs as well as other signs such as drop in egg production in layer chickens. Chickens can become sick when they come into contact with droppings of affected chickens or by breathing in infected droplets. The pox virus is spread by mosquito bites

Signs in live chickens

Discharge from the nostrils, difficult breathing, extended neck when breathing, sneezing, swollen sinuses and eye infection (conjunctivitis)

Signs in dead chickens

Red windpipe, mucous and plugs of pus in the windpipe and sinuses


There is no treatment for viral diseases. Antibiotics such as tetracyclines can be used to treat secondary bacterial infections which can complicate the viral disease

Control and prevention

Respiratory diseases caused by bacteria

Mycoplasma gallisepticum (MG)

Mycoplasma gallisepticum contributes to the respiratory disease complex in chickens. Chicks born from infected hens are infected in the egg. Chickens can also get the disease through contact with infected chickens. MG affects all types of chickens

Signs in live chickens

Discharge from the eyes and nostrils

Signs in dead chickens


Give antibiotics such as tylosin in the feed or water


Infectious coryza(IC)

This is a bacterial disease affecting layers, breeders and broilers. The chickens get sick after contact with the bacteria, for example, in drinking water or by breathing. It results in swollen sinuses and a drop in egg production

Signs in live chickens

Swollen face, difficult and fast breathing, discharge from the nose and eyes as well as green diarrhoea

Signs in dead chickens

Swollen sinuses and sometimes a watery jelly layer under the skin covering the head


Give potentiated sulphonamides in the water or tetracyclines in the feed to treat secondary bacterial complications. Sulphonamide treatment may have to be repeated


There is a vaccine available. It must be given twice and should preferably contain the C3 strain

Respiratory disease caused by fungi


Aspergillosis is an infection caused by fungi. Chicks are infected when they breathe in spores from the incubation machines at the hatchery and to a lesser extent from the environment, contaminated feed and litter. This infection is mostly seen in chickens kept in houses

Signs in live chickens

Difficulty breathing, fast breathing and open-mouth breathing

Signs in dead chickens

White areas in the lung




For further information consult your animal health technician, state or private veterinarian
Animal Health for Developing Farmers
ARC-Onderstepoort Veterinary Institute
Private Bag X05, Onderstepoort 0110


Compiled by Directorate Communication, Department of Agriculture
in cooperation with
ARC-Onderstepoort Veterinary Institute

Printed and published by Department of Agriculture
and obtainable from Resource Centre, Directorate Communication
Private Bag X144, Pretoria 0001, South Africa

This publication is available on the web:

Information provided by
Animal Health for Developing Farmers
ARC-Onderstepoort Veterinary Institute
Private Bag X05, Onderstepoort 0110
Tel. (012) 529 9158

Respiratory diseases
in chickens