Egg yolk peritonitis can be a life-threatening condition for a laying hen.  Luckily, this condition isn't common.  I've raised hundreds of chickens, many of them laying hens.  I've been fortunate to not have this happen with one of my laying hens.

Although the condition is uncommon, it does happen.  Getting swift treatment for your hen can be the difference between a hen that can go back to laying and one that you'll end up replacing.

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​Keep reading to learn what causes egg yolk peritonitis and how to spot it.

To understand what causes egg yolk peritonitis, you need to understand how the hen's reproductive tract works.  The hen's body is constantly getting eggs ready to lay.  The yolk of the egg starts to mature on the ovary.

Once the egg yolk is mature, the ovary releases it.  Normally, the yolk is 'caught' by the oviduct.  Think of the oviduct like a catcher's mitt in baseball.  The oviduct then funnels the yolk through the rest of the reproductive tract, where the egg white, membranes, and shell can be added.

In a hen that gets egg yolk peritonitis or EYP, the yolk isn't caught by the oviduct. Instead, the yolk moves into the body cavity of the hen.  It can attach itself to the peritoneum.  The peritoneum is a lining that separates the reproductive tract from other organs in the hen's body.  This can cause serious issues in the hen.

Most of the time, when an egg yolk ends up in the wrong spot, the body just resorbs the egg.  Sometimes, the yolk isn't resorbed and is instead treated as an infection in the hen.

The egg yolk is the perfect environment for bad bacteria to grow.  Bacteria in the body are attracted to the egg yolk and can create a nasty infection.

If the egg yolk isn't resorbed by the body, it can create a large, hard mass in the hen's abdomen. The yolk that wasn't resorbed by the body can prevent the oviduct from catching other egg yolks, leading to a snowballing problem of additional egg yolks not being caught.

The yolk can cause the peritoneum to swell.  The peritoneum is usually a thin membrane.  It can become quite swollen and sore. The space will also collect fluid.

The body has natural populations of bacteria, like E. coli, that can be attracted to the swollen and affected tissues surrounding the misplaced yolk.  The bacteria thrive in the yolk and surrounding tissues, causing an infection.

If the yolk and affected tissues become infected, the infection can quickly spread into the bloodstream.  Once in the bloodstream, the infection can harm other organs, including the liver or kidneys.  This can lead to death.

Egg yolk peritonitis is more common in hens that are coming off of the laying season, usually in the fall.  It can affect hens at any time of year.

​There are a few causes of egg yolk peritonitis.

-an egg not forming properly
-a swollen oviduct that is unable to catch the mature yolk properly
-an impacted oviduct due to previously abnormally formed eggs
-ovarian cysts
-ovarian cancer
​-twisting of the oviduct that prevents egg yolks from passing through

Thankfully, egg yolk peritonitis is not contagious. Even if a hen does develop an infection because of egg yolk peritonitis, she will not transmit it to another hen in the flock.

It is a good idea to separate a hen with EYP from the rest of the flock, even though she is not contagious.

Removing her from the flock will make it easier to give her specialized treatment.  She may need hormones or antibiotics that the other hens in the flock don't need.  Separating her will allow you to give her the medications that she needs.

​Her stress levels will also be lower if she is alone and comfortable.  Make sure that she has a constant supply of fresh food and water.  Keep her in a clean and warm space while she is being treated.

Egg yolks may be passed and resorbed without you even knowing it.  If the egg yolk is misplaced and peritonitis develops, you'll likely see signs that your hen is suffering.  At the first sign of possible egg yolk peritonitis, you may want to have your hen examined and start treatment.

​The earlier the treatment for EYP is given, the more likely your hen will recover.

One of the most common signs of egg yolk peritonitis in hens is the penguin-like stance that they exhibit.  Most hens carry their bodies horizontally, with the breast nearly level with the vent.

​Hens that are suffering of EYP will often stand up straight, like a penguin.  This upright stance relieves some of the pain associated with EYP.

Hens with EYP may stop laying.  This is also a common sign of egg binding, which is a different issue.  Egg yolk peritonitis can lead to poorly developed eggs.  You may notice your hen start to lay thin-shelled or soft-shelled eggs.

Egg yolk peritonitis is very painful and will affect your hen's activity level.  She may spend too much time in the besting box, almost like she's broody.  She may also go off of feed and water.

If the EYP becomes severe enough, there will be noticeable swelling in the abdomen that you can feel.  The swelling may be fluid-filled, but it's often hard and low in the abdomen (usually close to the vent).   When feeling the abdomen, you may feel fluid.  If you feel fluid in the abdomen, make sure that you aren't dealing with a case of water belly.

​Swelling that is large enough can impact the hen's ability to breathe. An overly swollen abdomen can push on the bird's lungs and respiratory tract, causing breathing difficulty.

Yes. With prompt and proper treatment, hens can recover from egg yolk peritonitis.

​More severe cases of EYP can also be treated but may require removal of the problematic ovary (usually the left one), which will likely affect the hen's laying ability.

It can be difficult to diagnose EYP at home with your hens.  Many of the symptoms are similar symptoms of other illnesses or diseases in chickens.

​For this reason, if you suspect egg yolk peritonitis, you need to have your hen looked at by a veterinarian that is experienced with chickens. You can find a list of certified poultry veterinarians through Poultry DVM or the Association of Avian Veterinarians.

At the vet clinic, the veterinarian will feel the hen's abdomen.  He/she will feel for swelling, soft-shelled eggs, eggs that are free in the abdomen, ovarian masses or cysts, or misplaced reproductive organs.

After a physical exam, the veterinarian will likely collect samples to run tests that will help determine the underlying cause.

The vet will likely take a blood sample to run a complete blood count or CBC.  This test is used to count the number of white blood cells.  White blood cells, or WBCs, are created by the body to fight off infection.

A healthy animal will have low levels of WBCs.  A high number of WBCs indicates that there is an infection and that antibiotics may be needed.

A coelomocentesis may also be performed.  This simple test is done by inserting a needle and syringe into the coelom, just below the keel.  Fluid is extracted from the coelom and can be viewed under a microscope to determine the type of tissues in the fluid.

The coelomocentesis is a very helpful test because it can also be used to tell veterinarians what type of bacteria is causing the infection.  Different types of bacteria should be treated with different types of antibiotics.  Knowing what type of bacteria is causing the infection will help your vet determine which type of antibiotic will be most effective.

​Your veterinarian may find it helpful to perform other types of tests while you are in the clinic.  X-rays and ultrasounds can help your veterinarian see if there is fluid or partially developed eggs in the wrong spaces.

The severity of the case will determine the best method of treatment.

In mild cases, your vet may only recommend supportive care.  This includes keeping the hen separate from the flock and providing access to fresh food and water. You may be given an anti-inflammatory medication to help relieve the swelling in the tissues around the egg yolk.   Anti-inflammatory medications may also help reduce the likelihood that your hen develops EYP again if the original cause was a swollen oviduct.

If an infection is present, antibiotics will be given.  These could be either oral or intravenous antibiotics. Oral antibiotics are given when an infection is present but is considered mild.  If the infection is thought to have spread, more aggressive antibiotics will be given through an IV.

​There are other options that can help a hen with EYP.

-Excess abdominal fluid removal
-IV antibiotics
-Oxygen therapy
-IV fluids to prevent dehydration
-Surgery to remove egg yolk tissue
​-Salpingohysterectomy- Spaying of the hen to remove the problematic ovary and egg tissue

In most cases, your veterinarian will give your hen a broad-spectrum antibiotic.  The most common bacteria that is seen with egg yolk peritonitis is E. Coli.  Other commonly seen bacteria associated with EYP are Klebsiella, Proteus, Staphylococcus, and Streptococcus.

Some common antibiotics that are used to treat infections associated with EYP include Baytril, Sulphonamides, Oxytetracycline, Gentamycin.

If your veterinarian does a coelomocentesis, he or she will be able to give a targeted antibiotic for the type of bacteria that your hen has.

​Treating the bacterial infection with antibiotics will help treat the case of EYP, but it may not prevent the hen from getting EYP again.  The underlying cause of the misplaced yolk needs to be determined to prevent EYP from happening again.

Egg yolk peritonitis is an uncommon problem in laying hens, so if you have a hen that's diagnosed with it, you likely have many questions.  Here are some common questions about EYP.

The process of producing an egg in the hen's body takes close to a month.  The egg starts as a yolk, which then moves into the oviduct. If a rooster and sperm are present, the yolk will be fertilized in the oviduct. The egg white, membranes, and shell are then added around the yolk before being laid.

​For more information about how eggs are produced (and what can go wrong in the process), check out the video below:

Egg-related coelomitis and egg yolk peritonitis are the same things.  They are two different terms used to describe an egg yolk that didn't get caught properly by the oviduct and became loose in the coelom.

Humans cannot catch egg yolk peritonitis from chickens.  However, always use caution when handling sick chickens, especially if you haven't gotten an official diagnosis from an experienced veterinarian.

​The symptoms of EYP can look like the symptoms of other diseases, which could cause illness in humans, so it's best to be cautious.

Yes, egg yolk peritonitis can be very painful for chickens.

Any time that there are swollen tissues in the body, it's painful.  If the tissues become infected, the amount of pain associated with the area will be worse.

​The pain associated with EYP is what causes most hens to have the characteristic penguin stance.  That awkward stance helps to alleviate some of the pain.

No.  If you suspect that your chicken has egg yolk peritonitis, please seek the help of a veterinarian.  This is a life-threatening situation that is very painful for your hen.  If you're seeing symptoms of EYP, your hen is likely in a lot of pain.

If your hen develops an infection with EYP, the infection can move quickly through her body and can kill her.  Most hens that start showing signs of EYP and have an infection will only survive as long as a week.

With proper treatment, your hen can survive.

I have seen people suggest colloidal silver as a possible treatment.  Do not give your chickens colloidal silver. There is no known use for silver in the body or in your chicken's body.  That's almost as silly as injecting mercury into yourself to 'treat' syphilis like they did in the 1800s.

This isn't the 1800s.  There are plenty of proven treatments that will help your chicken get better. Colloidal silver isn't one of them.

​Oregano has some antibiotic use in chickens, but it may not be good enough to keep your chicken alive. When you have a severe, life-threatening problem like EYP, use an antibiotic that will knock the infection out.

An egg-bound hen has an egg stuck in her oviduct.  This can happen for a few different reasons.  An egg-bound hen will spend more time in the nesting box than normal.  In fact, by definition, egg binding occurs when a hen fails to expel an egg after a few hours.

Egg binding is different than egg yolk peritonitis because the egg in an egg-bound hen is in the correct spot (in the oviduct), but the hen is having trouble getting the egg out.

A hen with egg yolk peritonitis may be referred to as a hen with internal laying.  The egg never made it to the oviduct to leave the body.  Instead, the egg is just in the body cavity with no way out.

An egg bound hen will usually have the following symptoms:

-abdominal straining
-wide stance
-sitting or squatting abnormally
-prolonged time in the nesting box
-inability to perch
​-wagging tail
​
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