Incidence of pendulous crop is low in flocks of chickens but appears to be increasing in turkeys. The crop is grossly distended and contains foul-smelling fluid, feed, and litter. Feed utilization is impaired, and severely affected birds become thin or emaciated. Survivors often are condemned or trimmed at processing to reduce contamination by crop contents.
The exact cause is not known, but a hereditary predisposition potentially associated with hyperphagia has been suggested in turkeys. Incidence may increase with erratic or excessive feed or water consumption from any cause, resulting in stretching and damage to tissues supporting the crop. Vagus nerve damage has also been postulated as a cause in rare cases. There is no known effective treatment.