Coryza Diseases in Chickens – Causes & Treatments

When raising chickens, it is crucial to know about the issues you might have to deal with at some point so that you are adequately prepared for them.

One of these is a disease. Most poultry keepers only focus on lymphoid leukosis or Marek’s. Nonetheless, infectious coryza is also a relatively common respiratory disease that can suppress your chickens’ immunity and be deadly for weaker birds. It is also called the catarrh, roup, or pip.

Coryza is a medical term for the common cold, which can also affect humans. Nonetheless, the infection is more severe than the common cold in humans.

Below are a few facts to help you understand this disease in your chickens and how best to handle it.

What is Coryza Disease?

Infectious coryza is an acute respiratory illness caused by Avibacterium Paragallinarum. This is a gram-negative bacteria. There is an illness that affects pheasants, quails, and turkeys and has the same symptoms as coryza.

Though often confused for the latter, this illness is thought to be caused by a bacterium other than Avibacterium Paragallinarum, so it is a different disease.

Coryza in chickens is sometimes described as a serious cold, but the illness is often worse than this and comes with long and short-term consequences, unlike a simple cold.

Coryza is a catarrhal infection affecting chickens’ upper airways, causing inflammation of the sinuses and leading to a swollen airway. These effects culminate in difficulty breathing for your bird.

The term catarrh, often used to describe coryza, refers to mucus membrane inflammation characterized by tissue swelling, profuse mucus discharge, blood vessel enlargement, and cellular debris.

Though the illness is typically acute, it can sometimes be chronic and lead to recurrent outbreaks spanning long periods.

Coryza is an airborne illness passed directly from one bird to another by contaminated feeds, water, dust particles, droplets, and bedding.

Chickens are highly prone to the disease in cramped spaces like a swap meet, live bird markets, and poultry shows when they are in close contact with an infected bird. If a hen is sick, she cannot pass on coryza to the chick, but the chick can become infected after it hatches.

The incubation period for coryza is 1-3 days. This period is followed by the rapid onset of symptoms for 2-3days. Your entire flock can become infected in about ten days.

You will rarely notice anything amiss within the incubation period since there are no overt symptoms of coryza in your chicken at this time.

In uncomplicated disease, the disease progresses in about 7-11 days. If your bird has coexisting infections, coryza can continue for more than a month.

Coryza Symptoms in Chickens

Infectious coryza has several signs that can inform you to seek prompt treatment for your chickens.

While some of these signs can be mistaken for another illness when considered separately, you cannot miss the diagnosis when you consider all the signs together.

Here are the common symptoms of coryza in chickens:

  • Facial swelling, often under the eyes, but the wattles and cheeks can also become swollen.
  • A pale comb.
  • Thick, sticky, foul-smelling discharge from the eyes and nares.
  • Conjunctivitis, which bubbles around the corners of the eyes.
  • Labored breathing or wheezing.
  • Sometimes when the lower respiratory airway is affected, you can hear rales that sound like crackles or wrinkled paper.
  • Decreased drinking and appetite.
  • Weakness and walking difficulty.
  • 10-40% decrease in egg production.
  • The eyelids might become crusty and stick together.
  • Occasional diarrhea.

If your chicken, unfortunately, dies from coryza, here are some post-mortem lesions you will notice:

  • Catarrhal inflammation of sinuses and nasal passages.
  • Adherence of the eyelids.
  • Tracheitis.
  • Caseous materials in the sinus and conjunctiva.
  • Conjunctivitis.

How do You Know if Chickens Have Coryza?

You can make a presumptive diagnosis of coryza based on the symptoms above in your chickens.

However, these are also symptoms of significant differentials of coryza, like fowl cholera, laryngotracheitis, avian influenza, vitamin A deficiency, mycoplasmosis, infectious bronchitis, swollen head syndrome, and Newcastle disease.

It is crucial to confirm the diagnosis by isolation and identification of a gram-negative bacterium. Polymerase Chain reaction (PCR) tests of live flocks provide accurate results. You can also settle for a bacterial culture.

Nonetheless, most experts agree that the PCR test is more accurate than the culture and uses fewer resources.

Can You Cure Coryza in Chickens?

Yes, thankfully, you can cure coryza in chickens if you catch it early. The ideal treatment alternative for coryza is a course of antibiotics, as the disease is caused by a bacterium.

These antibiotics should be prescribed by a veterinarian and administered according to the expert’s instructions. Using the wrong antibiotics is not only useless but might also predispose your bird to antibiotic resistance later.

Sometimes, a vet can run tests to pick the best antibiotic for your chicken. The common antibiotics for coryza in chickens are streptomycin, erythromycin, and sulfonamides like cotrimoxazole administered in water or food.

Though antibiotics will cure coryza in chickens, the affected bird becomes a carrier of the disease for life and will shed the bacteria time and again. This means that when you add new birds to your flock, they might become infected.

The cured chicken might also have relapses and require antibiotics. If a vet is too far to get to your chicken quickly, consider giving the bird a tablespoon of vinegar, water, and crushed garlic to relieve some symptoms though this does not cure coryza.

How to Prevent Coryza in Chicken

Disinfectants, drying, and heat can kill the bacterium that causes coryza in chickens. As such, you can protect your chicken by keeping their coops clean and dry.

Thoroughly wash the coops as frequently as need be. Moreover, change your clothing and boots when you visit different flocks.

For instance, when you go to poultry shows, change your clothes and boots before handling your chickens. This is because the bacteria can stick to them and transfer to your flock.

Quarantining all new birds, even when they look healthy, for not less than a month also goes a long way in preventing coryza in chickens.

Vaccinate all birds, even those that have been infected and recovered. The vaccination does not stop the recovered chickens from being carriers but prevents the manifestation of coryza.

The coryza vaccine is administered in two subcutaneous injections weeks apart. If you suspect that a bird in your flock is infected, test the whole flock so that you can take swift action for the infected ones.

What to do With Sick Chickens

When you notice a sick chicken, the ideal step before a vet arrives is to isolate it. This prevents the further spread of the disease among your flock.

The isolated fowls should be kept in a warm, comfortable place. Some breeders choose to depopulate their flock by culling the sick birds and replacing them with healthy ones.

This is an extreme measure because coryza is treatable and does not warrant culling.

Can Humans Get Coryza From Chickens?

No, fortunately, humans cannot contract coryza from their chickens, so it is not a cause of public concern.

Even consuming the meat and eggs of chickens suffering from coryza will not pass the bacteria to humans. The bacteria strain that causes the disease in chickens is not the same as the one that causes the same in humans.


The most significant takeaway from the above information is that good housekeeping will protect your chickens from coryza and ease the treatment of sick ones.

Removing soiled or damp bedding and cleaning up poop weekly go a long way in keeping coryza at bay and containing it.

The mortality of your flock after contracting coryza is 20-50%. The higher mortality often happens if your flock is made up of older birds since these cannot shake off the bacteria as well as young ones.

Stressed birds also have higher mortality rates from coryza than non-stressed ones.

avatar James
Hey, I'm James, a hardworking homesteader for more than 30 years. I enjoy the feeling of accomplishment that comes from tending my flock. I've raised chickens and ducks for eggs and meat for many years. I also have experience with other poultry too. Learn more

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