Ascites in backyard laying hens is one of the most common things I see both in the clinic and on house calls. The most common initial concern I hear from clients is that they believe they have a hen that is egg bound. These hens will have a very distended coelomic cavity (abdomen or belly) and walk with a penguin like stance, standing more upright than normal with a bit of a waddle. They also usually tend to have difficulty breathing, which is another common concern with clients.
Ascites is not a specific disease in and of itself, but rather, something that happens in the body because of various disease processes. Heart disease, liver disease, infectious diseases, and cancers can all lead to ascites fluid build-up.
In meat type birds, ascites, also known as Pulmonary Hypertension Syndrome (PHS), is related to a combination of genetics along with environmental and management conditions.
In laying hens, the most common cause I’ve diagnosed is secondary to ovarian neoplasia. The diagnosis is by necropsy so if my client doesn’t wish to have this done, I won’t be able to tell what the cause was.
Another not uncommon cause is yolk peritonitis, which may or may not be associated with infection. This occurs when a yolk is ovulated either directly into the peritoneal space or may make it into the oviduct and then is retropulsed, or moves in the wrong direction, back into the body cavity. The yolk, or even fully formed egg at times, causes inflammation which can lead to the fluid build-up. If bacterial infection in the oviduct is what caused the egg to retropulsed in the first place, this can also enter the body cavity.
Sometimes a cyst stemming from a persistent right oviduct can be the cause. This is the best case scenario since it is not stemming from a disease condition but rather a usually benign cyst formation.
So what do you do if you suspect your bird has ascites?
Ideally, have them examined by a veterinarian experienced with chickens. X-rays and ultrasound can be very helpful in diagnosis. An electrocardiogram might be helpful if the cause is related to PHS or other cardiac issue. Removal of the fluid will give the bird temporary relief in reducing the pressure on the internal organs and on the lungs and air sac system. This doesn’t fix the problem but does give the bird a better quality of life. If the problem is a cyst, the prognosis is much better but still must be drained on occasion.
If the bird is a meat bird, it is most humane to euthanize him earlier than anticipated to reduce suffering, though you may not know there is anything wrong until you find him deceased. If the others still have growing to do before they are processed, consider increasing ventilation and ensure a clean, ammonia free environment.
In the mean time, you can make your bird more comfortable by keeping her in a small quiet warm area with good ventilation to help her breath more easily. Make sure she has plenty of clean, fresh water and food that is easily accessible.
Other problems can mimic ascites, so don’t give up hope or automatically assume that your bird has ascites. These issues include obesity, egg binding and salpingitis. There are also treatments that can help your bird feel better including medications, therapies such as draining the abdomen, or surgical intervention.