16 Common Pet Chicken Illnesses (And How You Can Help)

Taking care of chickens is a big responsibility, as it is with any pet, and sadly, chickens are just as prone to getting sick as people are. However, the good news is that most conditions that chickens suffer from are treatable and are not transmissible to humans. You can learn to ensure your chickens live long and happy lives quite easily.

Our 16 common pet chicken illnesses are Aspergillosis (Brooder Pneumonia), Avian Encephalomyelitis, Avian Influenza, Botulism, Chronic Respiratory Disease, Coccidiosis, Fowl Pox, Impacted Crop, Infectious Bronchitis, Lice, Marek’s Disease, Mites, Newcastle Disease, Rot Gut, Roundworm and Salmonella. We’ll look at the symptoms of each and then how you can help.

What Illnesses Do Chickens Get?

1. Infectious Bronchitis

Chickens are very prone to infectious bronchitis and it is highly contagious. It is caused by a viral agent known as avian infectious bronchitis virus and it might be interesting to learn that this is a coronavirus (yes, just like the one that has been killing people since emerging in Wuhan, China) fortunately this one is not zoonotic (that means you won’t catch it).

Symptoms Of Infectious Bronchitis In Chickens

There can be many different symptoms associated with infectious bronchitis and it can be a little challenging to diagnose. If your chickens catch it and are not vaccinated – all of them will get it without exception. This can result in sneezing, coughing, gasping and in very young chickens it can cause severe respiratory distress.

What to do about it?

The best thing you can do about infectious bronchitis is to have your flock vaccinated because it can kill up to 60% of the flock if they get it. There is no treatment for the disease once they have it but it’s possible to use antibiotics to prevent secondary infections. It’s serious enough that your vet will have to instigate biosecurity protocols if your flock becomes infected.

2. Salmonella

Salmonella in chickens can be completely asymptomatic though it can also make some chickens as sick as it does people. Yes, it’s a bacterial infection which is completely zoonotic (that is you can catch it from your birds and yes, salmonella is pretty awful in people, so it’s best to treat it as soon as you’re aware that it’s there.

Symptoms Of Salmonella In Chickens

Your chickens catch salmonella by consuming it in the dirt around the area where the roam. It is not an indication of poor hygiene or lack of care and/or attention. If a chicken gets sick it will exhibit similar symptoms to people infect with salmonella – that is they may start vomiting, have very severe diarrhea and they will be running a fever and may have abdominal cramps.

What to do about it?

If you suspect that your chickens have salmonella or if you or any of your family contract salmonella (and more than 1 million people in the US will this year) – you need to contact your vet and get your chickens tested. If they are infected, the good news is that salmonella can be treated with antibiotics and your vet may be able to give some advice on cleaning up the environment to prevent reinfection.

3. Rot Gut (Necrotic Enteritis)

Necrotic Enteritis, commonly known as rot gut by poultry farmers, is a bacterial infection caused by Clostridium perfringens. It can be found in the soil, the dust of a chicken coop, chicken and other animal feces and even in litter. If it’s left untreated then it can eventually lead to severe mineral and vitamin deficiencies. All chickens can catch rot gut from the age of 2 weeks old and above.

Symptoms Of Rot Gut In Chickens

Rot gut might sound trivial but it’s not. It can cause ataxia (a set of nerve problems that can cause changes in gait and eye movements), intoxication (chickens appear to be drunk), diarrhea (and very severe bouts), depression (yes, chickens can get depressed and it’s obvious), feathers may appear ruffled and they may be reluctant to move. Rot gut can kill a chicken in hours in the most severe form.

What to do about it?

A vet will diagnose this condition based on lesions around the mucous membranes and by isolating the bacteria in a lab. It can be treated by a combination of antibiotics in their feed and water. You may also need to improve sanitary conditions around the coop to prevent it from recurring.

4. Aspergillosis (Brooder Pneumonia)

One of the easiest conditions to treat in chickens is Aspergillosis which is often referred to as brooder pneumonia as it is most commonly found in brooding hens. It is a fungal disease which is infectious but not contagious. It is caused by inhaling the spores of the fungus when they are heavy in the air. It usually occurs when your chickens have already been sick.

Symptoms Of Aspergillosis (Brooder Pneumonia) In Chickens

As you might expect by a condition caused by a chicken breathing in spores, Aspergillosis primarily affects the lungs. The clearest symptom of Aspergillosis is a chicken breathing very rapidly or struggling to draw breath at all. You may also find that your chickens are very drowsy, and they may start to refuse food while drinking more.

What to do about it?

Firstly, you can prevent this condition easily by ensuring that the chickens’ bedding is kept dry and clean, so it doesn’t breed fungus. It’s also best not to line the run with bark chips. You can use antibiotics to treat it but it’s very expensive and often it’s cheaper to cull the birds than to treat them. So, it’s best to avoid it.

5. Fowl Pox

Fowl pox is a viral infection which is noticeably slow in its progression. There is a wet form of fowl pox and a dry form. Each of these has different symptoms. The good news is that, mainly, fowl pox is not fatal in chickens, but it is unpleasant and can have a severe impact on egg laying until the disease runs its course.

Symptoms Of Fowl Pox In Chickens

The wet form of fowl pox tends to have lesions and plaques form in the chicken’s mouth and sometimes in the respiratory tract. Whereas the dry form appears on the bird’s skin and the lesions tend to form thick and unpleasant scabs. Both forms can cause a bird to stop eating, to become depressed and upset egg production.

What to do about it?

In areas where fowl pox is common, it’s recommended that you vaccinate your birds between the age of six to ten weeks. A single dose of vaccine confers a lifetime of immunity to fowl pox. As a viral infection – there is no treatment for the condition and infected chickens will have to muddle through until they either fight off the infection or die.

6. Marek’s Disease

Marek’s disease is a highly contagious viral condition in chickens. It’s named after the Hungarian vet who isolated the disease. Any chicken that is infected with Marek’s is likely to become a carrier of the disease for life. It’s spread from chicken to chicken by inhalation from the particles in the feather follicles.

Symptoms Of Marek’s Disease In Chickens

Marek’s causes tumors in chickens and these tumors can eventually kill the chicken. Early warning signs are paralysis of limbs, organ failure, difficulty breathing, depression and eventually death. It is also likely to suppress the immune system.

What to do about it?

The only treatment for Marek’s is vaccination. Sadly, vaccination does not stop birds from contracting Marek’s it only suppresses the symptoms of the condition. Essentially it counters the growth of the tumors associated with the disease. Most birds are routinely vaccinated against Marek’s due to its wide availability around the globe.

7. Avian Encephalomyelitis

Avian Encephalomyelitis or Tremovirus A as it is known when it infects other species of bird is a major problem for chicken owners and farmers. While it is unlikely to cause large numbers of death in flocks, it will interrupt egg laying and can cause permanent neurological damage in young chicks. It is common worldwide and can infect almost all bird species.

Symptoms Of Avian Encephalomyelitis In Chickens

Chickens with Avian Encephalomyelitis tend to suffer from ataxia (that’s nervous problems which can interfere with the way a chicken walks or they way they see), tremors (hence tremorvirus), paralysis, blindness, drooping wings, and a dramatic decrease in egg production. It is diagnosed through a blood test.

What to do about it?

There’s not much that you can do once chickens are infected by Avian Encephalomyelitis as there is no treatment for it – though any chicks that make it through won’t be able to get it again. It’s best controlled by vaccinating your flock and the vaccine can be given in water or via eyedrops (eyedrops work best).

8. Lice

The good news is that while chickens get lice, they cannot be passed on to you or your family. They suffer from poultry lice and they won’t eat people. Sadly, once your flock gets infected with lice they can become a severe problem pretty quickly as they breed and spread very quickly.

Symptoms Of Lice Infection In Chickens

If your chickens get lice then you should see them exhibiting some of these symptoms, fatigue, wings that are looking chewed, pale wattles and combs, a dirty vent, sagging wings, itchiness, a fall off in egg production, lice you can see on the chicken, lice eggs on the feather shafts.

What to do about it?

Lice should not be treated with “natural method” (which don’t work and prolong the suffering of the birds) but rather with an insecticide prescribed by your vet. You spray the chickens with the insecticide to clear out the infestation.

9. Roundworm

Possibly the most common parasitic infection in chickens is roundworm. Most of the time, however, it’s not going to be a big problem and your birds may not even fall sick at all. The trouble begins when the roundworm, which usually live in the gut of the chicken, get lost in the chicken and start to migrate to other parts of the body where they don’t belong.

Symptoms Of Roundworm In Chickens

If your chickens end up with roundworm that becomes symptomatic they’ll have appetite issues, runny, watery poop, their egg laying will suffer, they may mope off on their own, they’ll be very dehydrated and may not be able to keep their balance. In the worst cases, the worms end up in the oviduct and the eggs are laid with worm in them.

What to do about it?

The most common treatment is a deworming agent called Wazine. Unfortunately, Wazine is not good for humans and thus, you can’t eat the eggs for a period of up to 2 weeks following de-worming. If this treatment does not work, the vet can normally offer a stronger agent for follow up.

10. Impacted Crop

The chicken’s crop is a little shelf that sits just off the esophagus. It serves only a minor part in digestion in that food that is swallowed sits there a little while basting in salivary enzymes before being passed on to the stomach. One major cause of illness in chickens is when the crop becomes injured or impacted.

Symptoms Of Impacted Crop In Chickens

The first sign of an impacted crop is usually the chicken spitting back up their food because they can no longer swallow it. Then they may stop eating altogether or if the problem is very severe – it may interfere with the chicken’s ability to breathe.

What to do about it?

It’s a very simple operation to treat an impacted crop and some people try to carry it out at home – we don’t recommend that and would suggest seeing a vet, instead. An impacted crop may also be the sign of a bigger underlying problem and they will be able to diagnose that at the same time.

11. Chronic Respiratory Disease

It sounds terrible but, in fact, Chronic Respiratory Disease (CRD) in chickens is basically their equivalent of the common cold. It occurs when a bird which has been infected with Mycoplasma gallisepticum bacteria becomes distressed. The bacteria then migrates to the respiratory system of the chicken.

Symptoms Of Chronic Respiratory Disease In Chickens

It appears that your chicken has caught a cold. They start sniffing, coughing, sneezing and may become distressed in terms of breathing. Many chickens can have CRD without showing noticeable symptoms, so you need to keep a careful eye on them.

What to do about it?

Fortunately, the treatment for CRD is simply to destress your birds. Make sure there are no predators around, that their environment is clean and safe, and that you are keeping pests, etc. at bay too. You can get antibiotics to help with infection and there is also a vaccination available in areas that this is very common.

12. Coccidiosis

Cok-si-do-sis is how this is pronounced and it’s a parasitic disease. It can be fatal if left untreated but is normally not too severe as long as it’s caught early. The parasites can live just about anywhere and your bird can get it from soil, feces, or water or other birds. Sadly, it’s very infectious and if one member of the flock has it – it’s reasonable to assume they all do.

Symptoms Of Coccidiosis In Chickens

The symptoms of Coccidiosis being with birds looking a bit run down or off color (the combs and skin can become much paler), they may laze around not moving or appear to be weak, they will also eventually go off their food and the biggest giveaway of all is the bloody or sometimes foamy yellow poop that they give.

What to do about it?

It’s treated using a drug called Corid (a brand name for amprolium). It takes about 3-5 days to clear the infection out of the flock and is mixed into their drinking water. There’s no certain preventative against this parasite.

13. Mites

Mites are another common parasitic infection of chickens and oddly, there are several different kinds of mite that a chicken can pick up. Fortunately, they all tend to present with similar symptoms and they all can be treated in a similar fashion. That doesn’t mean that you can ignore a mite infestation, however, left untreated mites can kill a chicken.

Symptoms Of Mites In Chickens

Mites infest the skin and suck your chicken’s blood and this leads to feathers falling out, scabs over the feet and legs, a reduction in the color of wattles and comb, a noticeable drop in egg production, not wanting to roost for the night, bloody smears on the egg shells and visible clumps of mites on their skin if you examine them closely.

What to do about it?

You need to start with burning all the bedding because mites are happy to switch from chicken to bedding in an instant. Clean the coop completely. Don’t waste your time on diatomaceous earth – it doesn’t work. Do ask your vet to supply an insecticide which you can spray all over your chickens and kill the mites dead.

14. Avian Influenza

Avian flu can be a serious problem. Some strains are not only zoonotic (they can jump species including to humans) but are as deadly to humans as they can be to your flock. It is often thought of as “fowl plague” given the destruction it wreaks on flocks of birds.

Symptoms Of Avian Influenza In Chickens

There are many different types of avian flu some severe and some less so – the main symptoms of all of them include a loss of appetite, depression, a break in egg laying, discoloration (blue) of wattles and combs, diarrhea, coughing and sneezing. Mortality can reach 100% when it comes to avian flu in the most severe cases.

What to do about it?

Sadly, there’s not much you can do for the birds. If they’ve got avian flu they will either pull through or they won’t but you must notify a vet if you suspect avian flu. If the diagnosis is positive, they may need to quarantine you or your flock. It is a disease of “major economic importance” which means if you don’t report it – you may be in serious trouble and could face huge fines and even jail time.

Of all the disease chickens face on our list, avian flu is by far the most serious. There are vaccinations available for some strains of Avian Flu but rather like with flu vaccines in humans, it’s difficult to predict which strains will emerge where in the world and they may be partially effective or completely ineffective.

If you or your family have been exposed to any form of Avian Flu, then you should immediately contact your own physician or family doctor and discuss what steps you should take to protect your own health.

15. Newcastle Disease

Newcastle Disease which is sometimes called exotic Newcastle Disease but is more regularly known as virulent Newcastle Disease (VND) is a viral condition which can be passed between almost all domestic and wild bird species. It can cause influenza like symptoms in human beings but unlike Avian Flu it represents no serious threat to your health. It takes its name from Newcastle-upon-Tyne in the UK where the second recorded outbreak took place.

Symptoms Of Newcastle Disease In Chickens

There are wide range of symptoms in chickens for Newcastle and they include respiratory distress, depression, ataxia, muscular tremors, drooping wings, paralysis, diarrhea, tissue swelling, deformed eggs and reduced levels of egg production. Some birds will die from Newcastle, but others will recover within about a week.

What to do about it?

As with almost all viral conditions there is no known treatment for Newcastle. However, there is a vaccine which can immunize a complete flock and should, ideally, be given to every new member of the flock prior to their introduction to the rest of your birds. There are several different formulations of Newcastle disease vaccine and it’s best to discuss what’s needed for your chickens with your vet.

16. Botulism

Botulism is a very serious form of food poisoning. Whilst the bacteria can be used for beauty treatments (Botox is based on these bacteria, for example) it is liable to cause deadly infections in human beings. It is, fortunately, much rarer than salmonella which affects nearly a million people a year but the death rate from botulism poisoning is nearly 100% in human beings.

Symptoms Of Botulism In Chickens

In chickens botulism is just as bad as it is in people. They will normally collapse to the ground and be unable to stand. They cannot support their heads even. Some birds will simply die on the spot without any other symptoms being reported. Oddly, there is no sign of diarrhea or other symptoms you might associated with poisoning. If one bird is infected, it is likely that there are others.

What to do about it?

Sadly, there is no real treatment for botulism in chickens. The vast majority of affected birds are going to die. Death is caused by the bacteria paralyzing the muscles that the chicken needs to breath effectively. With careful nursing lightly affected birds may recover but you should not feed them or try and give them water as they are likely to choke to death until such a point as they can raise their own heads.


We hope that our guide to handling these 16 common pet chicken illnesses is helpful to you and that it stops you and your flock from facing more serious problems down the line. One thing that we’d like to stress is that if you don’t know why your chickens are sick – always consult a vet.

That way they can make a speedy diagnosis and ensure your flock makes a recovery. Waiting around for chickens to get well by themselves can be a very bad mistake and some conditions can kill a chicken in less than a day. It’s really important to take action as quickly as you can.

Here are some of my favorite products for chickens and their coops:

Darren Black

I'm Darren Black, the owner, and author of AnimalKnowhow.com. I am from Scotland, United Kingdom and passionate about sharing useful information and tips about properly caring for an animal's wellbeing.

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