Clean vent of a laying hen. The shape of the vent will change from a circular opening to a more oval shape as the hen goes into lay.
For an examination, evaluate the feathers to check for feather loss and how they are distributed. Loss of feathers around the back and back of the neck may indicate mating behavior by roosters. Check feathers at the base of the feather shaft to look for parasites such as lice, mites, and nits (lice egg packets). Feathers around the vent should be clear and free of blood or feces. Pasting of the vent with loose feces may indicate enteric disease. Check for scabs and blood around the vent, which are evidence of vent pecking and cannibalism. The two small bones at the sides of the vent are the pubic bones. They should be flexible and have space in between. If hens are in lay, this distance should be 5–6 cm. When the hen is not laying, the pubic bones are usually stiff and close together (1.5 cm or less).
Courtesy of Dr. Patricia Wakenell.