Sick Chicken? Chicken Diseases 101: Diagnosis, Prevention And Cure Tips

Whether you’re new to owning chickens or you’ve had them around since you were a kid, dealing with chicken diseases can be difficult.

As with any animal, a chicken cannot communicate an issue with you until a symptom shows up – and then diagnosing how serious it is and deciding what to do about it is can be both intimidating and difficult.

That’s where this post comes into play.

The internet is a big place. So to help you out, we’ve gathered information on some of the most common poultry illnesses to give you a reference guide to help diagnose your chickens and figure out what you can do to keep those guys alive, healthy, and layin’!


Chicken Illness And Prevention

So, what are we dealing with here?

The reality is that, like humans or any other living thing, chickens can get sick in a lot of different ways.

They usually live in a communal scenario; they hang out in a cramped space, they are exposed to the outdoors when not in their coop, and they live and walk around in their own waste.

Seriously, if humans lived like that I don’t know who wouldn’t be sick all of the time.

Diseases from chickens’ feces are quite common; infections and viruses can spread from rats, possums, and other rodents; from infected feed or waterers…and even from you!

That’s right, your clothes, boots, and hands can even be the culprits.

Some of these infections are very dangerous and can kill a chicken before you even know they’re sick.

The best measure you can take to protect your flock from illness is prevention.

This can be done through cleaning the coop regularly, keeping pests like bugs, flies and rodents out of the coop, keeping a clean supply of water available year round, and making sure that the food hasn’t gone bad (Or you haven’t fed them the wrong food in the first place). To learn which predators could potentially be invading your coop, check out this article here.

You can also strategically place certain herbs and plants around your coop to help prevent illness.

If you need more information on poultry disease control and prevention, check out this article.

Some poultry illnesses are worse in winter when life is a battle between keeping chickens warm and forcing them to remain all “cooped up.”

Others can be more likely in the warmer seasons when the flock is out for a night on the town, hobnobbing and brushing up against other wildfowl. Those close encounters can be perfect for a bacterial infection to spread like wildfire.

Diseases and infections can be spread from parent to offspring through the egg laying and incubating process, and can therefore be present upon hatching. (This is important to identify early, as you may want to consume your eggs. You may also want to find out how to clean and store fresh eggs correctly)

Other diseases may not present themselves until the chickens are fully grown. Also, adding a new chicken into the flock can open the door to all sorts of danger. 

If you need some information on how to properly introduce new chickens into your flock, including how to quarantine them, check out this article.

Alrighty then, feeling confused yet? Do you feel like your chicken’s impending doom lurks around every corner?

Relax! It’s okay.

These are all standard things that chicken owners have to watch out for and deal with from time to time.

We’ll help you figure out what could be going on with your flock.

Do I Have A Sick Chicken? [Symptoms To Look For]

So how do you know when your chicken is sick? What are some sick chicken symptoms to look for?

For starters, look for anything out of the ordinary. There are obvious symptoms, like diarrhea, mucus on their noses, lameness, and general paralysis.

But there are other less glaring signs as well.

  • Is your chicken acting sluggish? 
  • Bloating or swelling?
  • Are they looking drowsy, not eating or drinking, or even laying fewer eggs?
  • What about labored breathing? That can be a sign of one of several different respiratory diseases. The best way to check for that one is at night when everyone in the coop is calm and resting.
  • Is a cough what’s affecting your bird?

Here is a good video to show you a couple of options for chicken cough treatments.

Common Chicken Illnesses

The goal here is to highlight some of the most common poultry diseases. However, keep in mind that there are countless other diseases out there, and a veterinarian is just a phone call away.

If you have serious questions, don’t take chances.

There are some common poultry diseases and treatments that are easy to deal with, but others can be quick to kill. There are even some poultry diseases that affect humans!

So please be careful!

Alright, let’s take a look at the list of common poultry diseases that could be affecting your birds.

We’ll look at them below and get a good idea of what each one is. We’ll also look at symptoms and the options for each chicken disease treatment for broilers and layers alike! 

List of 15 Common Poultry Diseases (In Alphabetical Order)

#1. Avian Influenza

We start off with a disease that has shocked the world more than once: the Avian Influenza.

More commonly known as “bird flu”, outbreaks of the disease have become alarming to humans on a global scale because of the infectious rate at which it can spread, and kill off a flock – not to mention the possible transfer to humans as well.

If you suspect that your birds have avian flu, report it to your vet immediately and ask them for assistance.


The Avian Flu is a viral disease that can survive for a very long time. It spreads through contact with infected birds or infected surfaces.

Anything from an improperly disposed-of carcass to infected rodents, equipment, and even people can all spread the disease.


Milder forms of Avian Flu can lead to things like tiredness, diarrhea, breathing issues, a decline in eating, and a decrease in egg production.

However, if the outbreak is more severe, dark red and white spots can develop on the legs and combs of the infected chickens.

In addition, blood-tinged discharge from the nostrils is common as well as facial swelling and blue combs and/or wattles.

Is It Fatal?

Yes, the Avian Influenza can be extremely deadly.

Less dangerous strains can have a relatively low mortality rate, but during serious epidemics, a large portion (half or more, depending on the source) of the flock can die.


As previously mentioned, the Avian Flu is serious enough that it must be reported immediately. Even the strains from mild cases can mutate quickly and become very deadly.

To compound the issue, even if infected chickens are cared for and recover, they will continue to be infectious for a long time.

The best solution is unfortunately to separate the birds that carry the disease, and get rid of them, as there is no effective treatment available at this time.

You can read more about the Avian Flu here.

#2. Botulism

Next on the list is another worldwide sickness familiar to our collective ear: Botulism.

If you’re thinking, “wait, isn’t that when I eat something rotten and get really sick?” then you’re on the right track.

If you’re interested in learning more about Botulism in chickens, check it out.


Botulism in chickens is very similar to the condition in humans – namely, when a chicken ingests something infected with Botulism bacteria, it gets really, really sick.

The bacteria can come from things like pond scum, maggots, plant waste, and the classic – rotting meat.

Another source is insects who have eaten from infected meat.


Tremors and paralysis are common.  You may find your bird unable to stand or lift its head.

Eventually, the paralysis can extend to breathing, at which point you can lose the animal.

Is It Fatal?

Unfortunately, yes. So when it shows up, it’s not fun. 

But the good news is that while Botulism shows up on most lists of diseases (as it’s an intense one to deal with), it is fairly uncommon when compared to other diseases.


Chickens sick with Botulism can be given antitoxins from the vet, although they can be expensive. 

Another good idea is to get rid of the source! Whether it’s pond scum or the dead carcass over there, get it outta here!

If you’re interested in learning more about Botulism in chickens, check out this article.

#3. Bumblefoot

Another interesting one for us humans to relate to, Bumblefoot is a chicken’s version of a staph infection in their leg (hence the “foot” part…)


Coming from the soil in most cases, this bacteria can appear especially after a heavy rain disrupts any stagnant water that may be in the chicken’s environment.

Usually, an injury on the leg allows the bacteria to enter and infect.


True to its name, a chicken with Bumblefoot has some pretty gnarly-looking legs. They become pink and callused, and can eventually end up covered in sores.

If left untreated, eventually the whole foot turns dark blue or even black, becoming swollen and distorted.

Is It Fatal?

No, unless you just leave the infection to fester. This one is fairly easy to keep from becoming morbid.


Antibiotics are effective. Dietary change and even surgery are options as well. It’s a good idea to ask a vet on this one!

Here is a good source for more information on Bumblefoot in chickens.

#4 – Coccidiosis

While the name alone is a bit challenging, that’s just the beginning of the trouble.

This parasitic disease will literally turn your stomach, or more accurately, your chicken’s stomach. It shows up, like many parasitic diseases, in overcrowded and unsanitary environments.


Coccidiosis is a chicken disease that invades the bird’s intestinal tract.

The parasite is ingested from the chicken’s environment in its egg form and then reproduces, at which point more eggs leave through the chicken’s feces.

This, of course, leads to a vicious cycle in which eggs are littered around the environment, making it quite contagious (if you’re looking for further information, check out this article on coccidiosis).


The Coccidiosis parasites can create a huge amount of gut damage, leading to things like diarrhea with blood and mucus, as well as weight loss.

Ruffled feathers and listless activity are also signs that something is going on inside.

Is It Fatal?

Generally no, although severe cases can be.

More dangerous is the fact that Coccidiosis weakens a chicken, making them susceptible to other diseases while they are battling with the parasite.


There are quite a few ways to deal with Coccidiosis. You can get an anticoccidial agent like amprolium or toltrazuril, while antibiotics can be options if secondary infections occur.

A gentler alternative is using an essential oil like thyme, tea tree, or clove.

Easy preventatives include vaccinating the chickens and keeping the coop clean and dry.

Because the parasite become infectious in wet or humid environments, it is a good idea to keep not only the entire coop clean, but especially the area around feeders and waterers.

This can help prevent any future outbreaks.

#5. Fowl Cholera

Here we run into one of the granddaddies of chicken illnesses.

First diagnosed over a century ago, fowl cholera can be a doozy. It can also be one of the more serious diseases in winter, when chickens are closer together.


This one is another bacterial disease that can spread from things like rats, possums, and other rodents, as well as wildfowl that stop in for a visit.


When the outbreak is serious, the first symptom you might run into is death.

However, keep your eyes peeled for other symptoms of fowl cholera, that include fever, reduced appetite, heavy breathing, mucus from the mouth, diarrhea, and ruffled feathers.

Weight loss can be another sign, as well the bird losing the ability to walk. Signs of nearing death include swollen joints and feet as well as abscessed wattles.

Is It Fatal?

As implied by the first symptom, yes.

This one can be intense, as the symptom list is long and ugly, leaving plenty of openings for the grim reaper’s icy grip.


While there are antibiotics available, this is one of those sad cases where even if the chicken recovers, it’s still a carrier.

However, preventative treatments exist including vaccinations to keep the sickness from spreading to the rest of the flock.

Really, though, keeping those pesky rodents out is the best long-term preventative you can find.

You can get some more info on Fowl Cholera here (the first one under Nonrespiratory Bacterial Diseases).

#6. Fowl Pox

Also known as chicken pox (a much more reasonable use of the title, in our opinion) this chicken disease is a viral infection that can cause a good deal of harm on a flock.

Note: this is not the same illness that is seen in humans.


Fowl Pox spreads from direct contact between birds and can spread through scabs that have fallen off, skin that has been scraped, breathing, and even through a bird’s eyes.

Mosquitoes who have fed on infected birds can also spread the disease.


There are two kinds of Fowl Pox.

The “dry form” comes with warty, raised spots on featherless areas of the infected chicken. The sores can take a couple of weeks to heal and can lead to things like slowed growth, lethargic behavior, and fewer eggs.

The “wet form” comes with actual pox in the mouth and throat. These look a lot like canker sores and can cause respiratory issues if they’re serious enough.

Either form can come separately or work in concert together to wreak havoc on a brood.

You can learn more about Fowl Pox here.

Is It Fatal?

Not generally, unless the pox leads to secondary infections.


There is no known treatment available, but it spreads slowly, allowing for preventative measures to be taken.

This gives you the option to vaccinate the rest of the flock if desired.

#7. Infectious Bronchitis

Another one to add to our list of respiratory diseases, this incredibly contagious viral disease plagues chickens in particular, rather than birds in general.


As mentioned above, this one is very infectious and can be spurred on by factors like the age of the flock and the living environment.

The virus can spread through a number of transmissions including feed bags, dead birds, infected coops, and those good-for-nothing rodents. But most commonly it can spread via the air.


Chickens that have Infectious Bronchitis will eat and drink less and develop a watery discharge from their eyes and nostrils. They will begin to have heavy, labored breathing, and their egg production can drop.

However, while this is a common symptom we’ve seen multiple times before, often chickens who have contracted Infectious Bronchitis never recover to previous levels of egg production, and their egg whites can become more watery.

Is It Fatal?

Generally not.

While it can lead to secondary infections, most adult chickens can recover. However, chicks are highly at risk and can have high mortality rates.


Once again there is little to do once your chickens already have the virus, besides taking good, rehabilitative care of them.

However, if they are still chicks, you can raise the temperature of their environment by a few degrees and give them a mash to help them eat easier.

Vaccines are available to prevent contracting the disease, but it must be given early on in life (within the first 15 weeks) as eventually, it will stop the hen from being able to lay eggs.

If you think you’re battling with Infectious Bronchitis or another respiratory illness, here is some more information to help make the diagnosis.

#8. Infectious Coryza

Similar in many ways to Infectious Bronchitis (scroll down for a comparison of the two), Infectious Coryza is a bacteria-driven respiratory infection.


Most often, Infectious Coryza transmits merely when two birds make contact, although airborne transmission is another possibility.

Chickens who have recovered can carry the disease as well, so be careful when introducing a new chicken into your flock.


One of the ways to tell Infectious Coryza from Infectious Bronchitis is that Coryza usually involves facial swelling accompanied by a thick, sticky discharge from the eyes and nostrils.

This can sometimes become so intense that the eyes stick shut.

Another stand-out about Infectious Coryza is that the chickens just plain stink.

I know, I know, chickens always stink, but if things smell worse than normal, you might be dealing with more than just the chicken’s bachelor-scented lifestyle.

Is It Fatal?

Yes, but mortality rates tend to stay pretty low, at around 20%.

It can get up around 50% at times, but either way, even recovered chickens are left weakened and susceptible to secondary diseases and infections.


This is a bacterial infection, so antibiotics and antibacterials are both options. As always, though, there can be restrictions and both should be used on animals with care.

Consult a vet!

Here’s a bit more information on Infectious Coryza.

#9. Lymphoid Leukosis

This is one of the sadder, more intense diseases on the list.

It is a viral, tumor-forming disease that targets the organs of adult birds in particular.


Carriers are infected for life, and can pass on the virus both through direct contact and through their eggs.

Unfortunately, it is very hard to know when this is happening, as so much of the damage takes place inside before exterior symptoms reveal what’s going on.


As is so often the case, egg production can slow in an infected bird.

However, beyond that, weakness can gradually increase along with comb regression, an enlarged abdomen, and a loss of appetite along with emaciation.

If greenish diarrhea develops, it is a sign that the bird is terminal.

Is It Fatal?

Not surprisingly, this one is a yes.

Once Lymphoid Leukosis reaches a point where it can be detected, many birds already have tumors on their organs and may die within weeks.


There is currently no known treatment.

Once a bird is diagnosed, do not let them reproduce or come into contact with other birds, to prevent spreading the disease further.

Once again, here is a bit more info if you think this might be a problem, and want to pursue a more detailed self-diagnosis.

#10. Marek’s Disease

Similar to Lymphoid Leukosis, Marek’s Disease is another one of the nastier types of illnesses.

A bane to younger chicks in particular, this tumor-driven virus affects the nervous system.


While it does not spread directly from parent to egg, Marek’s disease is highly contagious.

It transmits through the air via chicken dander/dust and can lie dormant in a seemingly healthy host for as long as a year.


Lameness, paralysis, drooping wings, weight loss, enlarged feather follicles, paleness, loss of appetite, blindness, and reddened, bloody looking shanks (lower legs) can all be signs that something is going on.

Is It Fatal?

Yes. Marek’s Disease has a very high death rate.


You can only vaccinate against Marek’s Disease before tumors develop.

But even then, the vaccine is only good for preventing the tumors themselves. Even vaccinated chickens can still be carriers.

If you’re interested in learning some more information on this one, you can find it here.

#11. Mushy Chick

What a charming name… for a sad and grotesque chicken disease (who comes up with these?).

Officially known as Omphalitis, “Mushy Chick” is a disease that infects new chicks shortly after hatching.More information on Mushy Chick disease can be found.


When a chick is born, its navel needs to heal.

In the short time between hatching and healing, however, the navel can become infected if it comes in contact with a dirty environment, such as soiled eggs, unclean hatching boxes, etc., which can lead to infection.


External navel infection is the obvious one. 

Others include abnormally large, unused yolk sacs, very bad smelling peritonitis (a swelling infection of the abdomen), seeping out of the navel, edema in the lower skin of the chick, dehydration, and even blood poisoning.

Is It Fatal?

Sadly, this one is fatal, with most infected chicks dying within a few days.


While there is little you can do other than comfort the infected chicks, some sources claim that antibiotics can give the chick a chance at recovery – although this is a long shot.

Either way, make sure to keep them away from the rest of the flock to avoid contamination of other chicks.

Prevention can be easily attained by keeping your hatchery clean – one of the many rules of raising healthy chicks and creating a good environment for them.

More information on Mushy Chick disease can be found here.

#12. Newcastle Disease

The next on our list of diseases in chickens (and another poultry respiratory disease), this viral infection attacks the nervous system and can vary in its intensity.


Newcastle Disease can spread short distances through the air, but it is more likely to be transmitted through contaminated “outsiders”.

Wild birds, dirty equipment, and your own shoes can all spread the infection.


Depending on how bad the case is, chickens can have wheezing, running nostrils, heavy breathing, swelling in the face, paralysis, trembling, and twisting of the neck, like this:

Other typical symptoms include eating and drinking less, and a decrease in egg production.

Is It Fatal?

Yes. Once again, the intensity factor can affect the numbers quite a bit, but mortality rates for Newcastle Disease can be as low as 10% and as high as 80%!


There isn’t a treatment at this point, so the virus must be left to run its course.

However, this is a serious enough disease that, at least in the U.S., it must be reported if you suspect your flock has the disease.

Separate the animal to prevent the disease from spreading, and give them plenty of TLC while they recover. One possible solution is to give them Vitamin A.​​​​ 

Also keep an eye out for secondary infections, which can usually be combated with antibiotics.

Vaccines are available to help prevent any future outbreaks as well.

Here is a good source for further information if needed!

#13. Salmonellosis

This bacterial disease can show up in a number of different forms including Arizonosis, Pullorum disease, fowl typhoid, and paratyphoid (see the breakdown here).

It is also more dangerous during cold seasons when chickens are living in close quarters due to the weather.


This one is, unfortunately, able to spread vertically (from parent to child) as well as horizontally (between adult chickens).

The latter can come in many forms, including an infected coop, food, boots and hands, rodents, bugs, and the addition of new birds to the flock.


Chickens infected with the bacteria can show signs of lethargy, puffy eyes, ruffled feathers, dehydration, lowered egg production, white, chalky diarrhea and pasty vents.

Is It Fatal?

Yes. This one can be deadly.


Probiotics in a supplement form or even yogurt can help fight off the infection.

In addition, to help prevent further outbreak, clean up the coop and take measures to keep bugs and rodents out and the food and water clean from contamination.

Winter can be harsh, and in cold conditions your chickens are susceptible to disease if they don’t have adequate water or a healthy environment. You may want to check out our articles on How Cold Is Too Cold For Chickens, and How To Keep Your Chicken Water From Freezing for some top tips and recommendations! 

#14. Scaly Leg

This one is a basic infection with a simple (and gross) cause: mites.

It’s true. Mites exist. They’re an unfortunate part of life. And in the case of Scaly Leg, it can cause a lot of issues.


Mites burrow down into the skin of the chicken, causing particularly bad damage to their legs and feet.

The mites spread from contact between the chicken and rodents, wildfowl, or other chickens.

It can be hard to see initially, as the mites are too small to see with the naked eye, but the symptoms can be a quick indicator of what’s going on.


Roughness and unevenness, as well as straight-up deterioration of the skin in the legs and feet, are obvious signs of Scaly Leg.

Is It Fatal?

No. Although if left untreated, secondary infections can be a danger.


There are plenty of options available.

You can suffocate the mites with topical ointments like vegetable oil, olive oil, coconut oil, and even petroleum jelly.

Diatomaceous earth is a good option as well. Ivermectin can be used, but please consult a vet before you do.

If you think you’re dealing with Scaly Leg and need more information, you can find it here.

#15. Thrush

Last but not least, we come to Thrush, or Candidiasis as it is officially called. Much the same as the infection seen in humans, Thrush is a fungal disease that can come from a number of sources.


Thrush can be transmitted through moldy feed, water, or other contaminated surfaces.

The long-term use of antibiotics can also make chickens more susceptible to the fungal disease.


An oozy white secretion between the neck and the body is common, as well as overeating, lethargy, ruffled feathers, and a crusty vent area.

Is It Fatal?

Not particularly. As with all diseases, if symptoms go unchecked it can become dangerous, but this one is pretty easy to address.


Feeding probiotics as a supplement or in a form like yogurt can be very helpful, and an antifungal medication from the vet is a quick and effective solution as well.

Obviously, removing the source of the mold is also imperative, as the fungus can otherwise be re-ingested.

Here is a great follow up source for dealing with fungal infections like Thrush (second down on the list!)

Wrapping Things Up

Now, if none of these more common diseases checked off what you’re dealing with at the moment, don’t despair.

There’s still hope!

If you’re a fan of’s symptom checker, you can try out this cool chicken symptom checker here to narrow down your search a bit further. Also, remember to call the vet if things are looking serious!

Now that you’ve got the rundown on what your chicken is dealing with, you can go help out your flock!

But before you do, please share this post!

And let us know in the comments below what your chickens were diagnosed with, and what you did to treat them.

List Of Chicken Diseases

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