Similar to egg binding, Peritonitis (an indicator of internal laying), is a distressing issue that can occur with laying hens. Internal laying is a disorder where the yolk of the egg, rather than being laid in a normal manner, is not taken up by the oviduct and instead is deposited in the abdomen. This can be a genetic use, but often times it follows an incidence of infection or trauma to the oviduct, such as a thin shelled egg breaking inside the hen. 

    Internal laying by itself is not always an issue Occasionally a hen will lay internally for no apparent reason and the yolk will simply be absorbed back into the body without complications if there are no bacteria present. The problem results when bacteria are present and when eggs build up inside. Egg yolk is a rich medium for bacteria growth, and a buildup of eggs internally can provide a playground for infection. This infection is known as peritonitis. If your hen continually lays egg after egg internally, the yolks can not only harbor and grow bacteria, but all the yolk material hardens and puts pressure on the internal organs. The hen’s body reacts to the yolk material and bacteria by producing a serous fluid. This fills the coelom (abdomen). Chickens do not have a diaphragm, so when the abdomen fills with fluid, the fluid can actually go up and fill the lungs making it difficult for the bird to breathe, causing her to adopt a penguin like stance.

​

Symptoms can include:
Feces accumulating on the feathers below the vent
Weakness
Loss of appetite
Lethargy/Depression
Hard swollen abdomen
Respiratory problems (holding beak open while breathing with neck extended)
Dark comb and waddles
Penguin stance; abnormal waddle