Respiratory Infections In Backyard Chickens

Updated December 11, 2020

What if I told you that your backyard chickens are carrying a respiratory illness? Even if they look perfectly fine. You’d have every right to be offended.

Well the truth is that most flocks carry more than one disease, and yet many never seem to have a problem. You’re about to find out why. You’re also going to learn what to do when one breaks out.

Respiratory infections are the second most common reason backyard chooks come to the vet. They can be very frustrating to control, and even harder to make sense of via Google. Let’s start with what they look like.

Signs Of Respiratory Infections

You may see some or all of:

  • Sneezing and coughing
  • Runny eyes and nose
  • Coughing
  • Laboured or fast breathing
  • Gasping & mouth breathing
  • Lethargy and poor appetite
  • Sinusitis

These all look similar to the symptoms of colds and flu in people, with one exception: sinusitis. To see it, go back to the picture above. On the left is a normal chicken and on the right is one with swollen sinuses (arrowed).

Common Respiratory Infections

There are many possible causes of cold or flu-like illnesses. Some are rare, others mainly affect the young. An Australian backyard chicken owner only has three common diseases to consider*.

  1. Mycoplasma is a tiny bacteria that lives in the airways. On its own it usually produces mild signs known as chronic respiratory disease that slowly worsen over time. It’s impossible to eradicate and extremely common.
  2. Infectious Bronchitis (IB) is a virus that causes a shorter period of more intense symptoms of cold or flu. A clue that it’s IB is that most birds appear to recover, and then start laying eggs with obvious shell abnormalities. These birds are carriers.
  3. Infectious Laryngotrachetitis (ILT) is a herpesvirus that produces a more severe respiratory illness, sometimes causing death. Blood is often seen in the mouth or throat. Birds that recover tend to remain carriers.

The worst infections happen when several diseases occur together. Both IB and ILT are more severe in birds who carry mycoplasma. Additionally, all three infections are made much worse by secondary infections with bacteria such as E. coli.

It’s the birds with these mixed infections that end up at the vet most often. But that’s not all. Infection alone doesn’t explain everything.

Management & Care Factors

The way you look after your chickens has a major influence on whether a disease is a problem or not. These are the five important habits of successful chicken keepers:

  1. Quarantine. Try very hard to keep a closed flock, with no new arrivals. ILT and IB can come in on a healthy-looking chicken and devastate a flock. Even mycoplasma can be introduced into naive birds.
  2. Buying from quality breeders. Good breeders will vaccinate their flock and raise hens free of the common diseases. This is still unusual in the heritage breeds but very common with commercial breeds like HyLine or ISA Brown. However, click here to see why heritage breeds live longer.
  3. Keeping litter clean & dry. Wet, soiled litter in the coop causes two problems. The first is the release of ammonia gas from urine, which is toxic to the respiratory tract and makes infections worse. The second is aspergillus air sac infection from fungus growing in moist litter.
  4. Avoiding stress and overcrowding. Most people do this quite sensibly, but it still needs mentioning. Some of those silly little hutches on eBay can be worse than a battery farm.
  5. Nutrition. Once again, not rocket science, but there’s still the persistent idea that chickens can get by on table scraps. Read more about good chicken nutrition here.

Treatment Of Respiratory Infections

The correct treatment relies on an accurate diagnosis. Realistically, this is almost never achieved in backyard poultry medicine. Therefore, it’s important that your vet chooses an antibiotic with the following features:

  • Efficacy against both mycoplasma and E. coli
  • Ease of use
  • Affordability
  • Safety to chickens
  • Food safety

I can’t stress the last point enough. Certain antibiotics should never be used for routine treatment when there are better and safer choices.

Vets who treat chickens regularly are familiar with which drugs work and which can be used in egg-producing chickens. We will also be able to guide you on the correct time, called a withholding period, before eggs can be eaten again.

Related: The Number One Illness Of Chickens | Fox Danger In The City

* It’s important to mention that this regional list misses four diseases exotic to Australia: two (metapneumovirus & ornithobacterium) are probably mild but I am unfamiliar with them, another two (Avian Influenza & Newcastle Disease) are extremely important to detect quickly if they arrive. Yet another reason to take that sick chook to a vet!

Have something to add? Comments are welcome below and will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.


6 Replies to “Respiratory Infections In Backyard Chickens”

  1. Good morning. I have just lost 2 of my wee girls within a week. Both went downhill very quickly. Only managed to get one to the vet in time but that was too late. Both were uneasy with walking, unable to lift their heads within just a few hours. All my girls were from a repeatable breeder and were vaccinated. They have said that it would have been a respiratory illness due to the huge amount of rain we have just had. My other 2 girls seem healthy and a good heavy weight. I have taken apart their outside coop and they now sleep under the patio. They are free range during the day. Stopped scattering their grain onto the lawn in case they local pigeons carry something as they share the grains. I have been told that this is quite common at the moment due to all the rain. Coop and nesting boxes always kept clean. Is there anything else I can do? I love my wee silkies and would be devastated if I lost anymore ☹️

    1. Hi Dee. There is probably not a lot more you can do after excluding all contact between wild birds and your flock apart from separating those who may yet not be infected and hoping no transmission has occurred. HOWEVER, your comment is also slightly concerning. It is a very timely reminder to always be aware of the more serious respiratory diseases of poultry, especially Newcastle disease, which is known for causing rapidly progressive respiratory and nervous system signs. In Australia, Newcastle disease is considered exotic and notifiable and is a disease of great importance. Please bring it up with your vet if there is any possibility. This link is for Victoria but there is a similar page for each state.

  2. Thank you for the information. I am particularly interested in the treatment of Mycoplasma as 10 of my birds are being treated at the moment. We have been told to consider culling our flock (45) as we shall never be rid of it. Also having to wait 6-12 months before starting with chickens again. Would you agree? I noted that you have mentioned it doesn’t survive long in the environment?
    We are quite devastated but trying to do the right thing. Would most back yard birds carry this disease?

    1. Hi Carol. Probably nearly all non-commercial layers carry mycoplasma from a young age. Culling the flock would only make sense if you could be sure that the next flock could come pathogen free (typically as young commercial-breed chicks who have been fully vaccinated and not mixed with birds from other origins). Otherwise, it will be best to look at improving their husbandry and environment so that the mycoplasma does not cause excess illness. In backyard flocks, it can often coexist with healthy chickens if everything else is okay and cause few issues other than occasional upper respiratory tract signs and reduced egg production.

  3. Hi,
    Thanks for your help re the respiratory diseases.
    How can we disinfect both the coop the earth in the outside runs?

    1. Hi Graham. None of these diseases persists long in the environment so the focus is really on having a clean flock, not the housing.

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