CHICKENS AND EGG YOLK PERITONITIS (EYP)

For those of you who share your backyard with beloved hens, you’ll know they quickly become much loved members of the family. Along with fresh eggs and wonderful personalities, chickens can sometimes develop reproductive issues, and one of the more common conditions we see in laying hens is Egg Yolk Peritonitis (EYP).

Egg Yolk Peritonitis occurs when egg yolk material, instead of being properly enclosed within a shell and laid normally, leaks or is released into the abdominal cavity. This can happen due to internal laying, oviduct dysfunction, infection, or hormonal imbalance. The yolk material inside the abdomen triggers significant inflammation and often secondary bacterial infection, leading to pain and systemic illness. Hybrid laying hens and birds that are high producing layers are particularly predisposed.

Early signs can be subtle, so it’s important to watch for changes in your hen’s normal behaviour. You may notice lethargy, spending more time fluffed up or sitting, reduced appetite, decreased egg production, or laying abnormal eggs such as shell-less or soft-shelled eggs. As the condition progresses, hens often develop a swollen or distended abdomen that may feel fluid filled, adopt a wide based stance, or show laboured breathing due to pressure from abdominal fluid. Some birds may also have soiling around the vent or show signs of discomfort when picked up. Because chickens instinctively hide illness, even mild signs warrant prompt veterinary attention.

Diagnosis is usually based on clinical examination, history, and sometimes imaging such as ultrasound or radiographs to assess fluid and reproductive tract changes. In some cases, sampling abdominal fluid helps confirm infection and guide treatment choices. Treatment depends on severity. Mild to moderate cases may be managed with antibiotics, anti-inflammatories, pain relief, and supportive care including fluid therapy and nutritional support. In recurrent or chronic cases, hormone therapy to suppress further egg laying may be recommended to allow the reproductive tract to rest. In more advanced situations, surgical intervention to remove infected material or perform a spay procedure may be discussed, although this carries higher risk in unwell birds.

Prevention focuses on supporting overall health and reducing excessive laying where appropriate. Providing a balanced diet formulated for laying hens, ensuring correct calcium levels, maintaining a healthy body weight, minimising stress, and seeking early veterinary care for abnormal eggs or reduced laying can all make a significant difference. If you notice your hen seems “not quite herself,” has a swollen abdomen, or stops laying suddenly, it’s always best to have her assessed early. Prompt treatment greatly improves comfort, welfare, and long term outcome for our feathered companions.