Crop impaction resulting from feather ball formation in caged layers

Abnormal behaviors in commercial poultry, including feather pulling and pic a, have been known to occur when birds are exposed to an unfamiliar environ ment. We report here the development of crop impactions resulting Dent feat her ball formation. Twelve specific-pathogen-free (SPF) chickens were place d in one of three cages housed among a commercial layer hock in three diffe rent buildings on a farm site. Three weeks after placement, the birds were removed from the cages and given a physical exam. Chickens were thin, and o ne bird in each of the three caged groups had a palpable mass at the level of the thoracic inlet. Ar necropsy, a mass was noted in the crop. Upon furt her dissection, a wet, foul-smelling mass consisting of feathers and feed d ebris was recovered. Results from our case indicate that unfamiliar surroun dings can cause pica in birds. Hence, avian researchers and veterinarians p lanning to introduce new birds into a flock, i.e., SPF birds, should consid er the birds' previous environmental conditions prior to placement because sudden placement in unfamiliar surroundings can result in pica.