These information sheets are provided for your interest. They should not replace veterinary advice from your veterinary surgeon.

Whilst every effort is taken to ensure the accuracy and completeness of the information provided at the time of writing, your specific circumstances must be discussed before advice can be given.

Respiratory Disease in Chickens

Whether you have a few backyard chickens or a flock of 1000, respiratory diseases can be a significant problem when trying to maintain a healthy flock. A wide range of diseases can cause respiratory signs in chickens....the most common signs you will see in your chickens are:

  • Sneezing
  • Open mouthed breathing
  • Wheezy/gurgling breathing sounds
  • Ruffled feathers
  • Discharge around the nostrils and eyes
  • Head shaking 

So what are the most common causes?


This is found in the environment so all chickens are likely to come into contact with this organism at some point in their life, but it doesn't always cause a problem. Mycoplasma is likely to cause disease when the birds are stressed, have another infection, if there is a lot of dust in the environment or if lots of birds living together are infected. Mycoplasma is hugely infectious so can spread rapidly through a flock once it has taken hold. Once diagnosed by a vet there are a few options for treating mycoplasma, with the easiest being soluble Tylosin which is added to the drinking water. To prevent disease you need to keep stressors to a minimum, keep the environment clean and dust-free, ensure your chickens are free of other diseases, and there is the potential for a myocoplasma vaccine if you are particularly concerned.

Infectious Bronchitis

Caused by a highly infectious virus (coronavirus), this causes respiratory signs but also a characteristic drop in egg production. You may also notice that the eggs from affected birds have soft, misshapen or 'crinkled' shells. Mortality rate is higher in young birds. The disease can be diagnosed by post-mortem examination or by taking swabs from the throat to look for the virus. Unfortunately there is no treatment for IB but if you suspect a secondary bacterial infection then antibiotics may help. There are vaccines available which are given to chicks and these may help protect against disease.


Chickens living for long periods of time in a dusty environment, or if ammonia levels in the air are high, can show significant respriatory disease. The lining of a chicken's airways are particularly sensitive and can therefore become inflamed by dust particles or ammonia. Try to use a bedding that doesn't give off much dust, and provide adequate ventilation to chickens living inside. Regularly removing faeces can help keep the ammonia levels down.


This disease is caused by the worm Syngamus trachea, with the adult worms living in the chicken's trachea. Earthworms and snails become infected by ingesting the worm eggs dropped on soil in chicken faeces, then chickens acquire the disease by eating infected earthworms/snails. The worm larvae cross the intestinal wall and travel to the lungs in the blood-stream, eventually entering the lungs and setting up residence in the trachea. This causes signs like coughing, head-shaking and the chicken may present with the characteristic 'gaping' mouth appearance. Young birds up to 8 weeks old are particularly susceptible, however treatment and prevention of gapeworm is easy....just keep up-to-date with your worming regime! Any licensed poultry-wormer should do the trick.


Other less common causes of respiratory disease in chickens include:

Avian Rhinotracheitis 

Sometimes called swollen-head syndrome, this respiratory virus mainly affects turkeys but has also been associated with chickens. Infection on its own will rarely cause clinical disease, but if the chicken is also struggling to fight another infection then respiratory disease is more likely to be seen. Unfortunately there is no definitive treatment except the use of antibiotics to control any secondary bacterial infections.

Infectious Laryngotracheitis 

This herpesvirus causes significant inflammation of the upper airways, and can have a high mortality in chicken flocks. As with most viral infections there is no definitive treatment except for trying to manage any secondary problems, such as secondary bacterial infections.

Avian Influenza (bird 'flu)

This is a notifiable disease that has had a lot of press-coverage in recent years due to the potential for it to spread to humans. It was identified in wild birds in the UK in 2018, but has not been found in domestic or kept birds. As well as the typical 'flu-like' symptoms you may expect to see in a chicken, you may also see a swollen-head, respiratory distress and and diarrhoea. The virus is spread via direct contact, either by introducting an infected bird to your flock, bringing the virus to your birds on contaminated material or by wild-birds visiting your chickens. If you at all suspect AI then please contact us at Evolution and we can give you further advice or come and check your poultry ourselves.

Main points to prevent against respiratory disease in chickens:

  • Keep the environment clean and dust-free, and keep stress to a minimum
  • Vaccinate
  • Quarantine any new birds before adding them to the original flock! This lets you check they are healthy before introducing them to your birds
  • If you spot any ill birds, separate them immediately to prevent the spread of infectious disease