When an egg is laid, the vagina everts through the cloaca to deliver the egg. If there has been injury to the vagina, such as from a large or double-yolk egg, or if the hen is fat, the vagina may not retract immediately, leaving it exposed for a short time. This may result in cannibalism (see abdominal blood and fat pad photographs).
When the protruding organ is pecked by other hens, the complete oviduct and parts of the adjacent intestinal tract may be pulled from the abdominal cavity (“peckout”). Bleeding from the vent occurs as a result of pecking.
Cannibalized hen, with blood clotted in the abdomen.
Courtesy of Dr. Rodrigo Espinosa.
Cannibalized hen, with thick abdominal fat pad.
Courtesy of Dr. Rodrigo Espinosa.
Hen with prolapse of the oviduct hiding in the nest.
Courtesy of Dr. Rodrigo Espinosa.
Hen with prolapse of the oviduct with swollen vent.
Courtesy of Dr. Rodrigo Espinosa.
Cannibalized hen, with blood clotted in the abdomen.
Courtesy of Dr. Rodrigo Espinosa.
Cannibalized hen, with thick abdominal fat pad.
Courtesy of Dr. Rodrigo Espinosa.
Hen with prolapse of the oviduct hiding in the nest.
Courtesy of Dr. Rodrigo Espinosa.
Hen with prolapse of the oviduct with swollen vent.
Courtesy of Dr. Rodrigo Espinosa.
Alternatively, the vagina swells, cannot retract, and remains prolapsed (“blowout”).
The hen dies from blood loss or shock (see hen in nest and swollen vent photographs).
Prolapse of the oviduct has been associated with the following:
excessive or premature photostimulation
poor body weight uniformity
early laying (inadequate body size)
large eggs
double-yolked eggs
obesity
Cannibalism may be prevented by beak trimming, managing light intensity, maintaining appropriate stocking density, and avoiding nutritional deficiencies.
