Infectious stunting and pancreatic fibrosis in broiler chickens in Saskatchewan.

Two broiler flocks contained 0.5 and 3% small chickens. The small chickens were approximately one-third the size of their penmates, were very active, and retained much of their chick down. They had distended abdomens with full intestinal tracts, often containing undigested feed. In many, the pancreases were thin, white, and firm because of loss of exocrine tissue and replacement by fibrous tissue. Many had skeletal changes suggestive of rickets. In a survey of 48 broiler flocks for small birds and pancreatic lesions, five flocks had a noticeable incidence of small chickens, varying from less than 1% to a maximum of 2%. In 33 of the flocks surveyed, a low incidence of pancreatic lesions was found in birds at the processing plant. No correlation was found between a noticeable number of small birds at the farm and pancreatic lesions found at processing.