Chronic orthopaedic disease in adult male broiler breeding fowls.

An assessment has been made of spontaneous orthopaedic disease in 100 male broiler breeding fowls aged between 51 and 62 weeks. Lesions were identified in the pelvic limbs of 92 birds, 85 of which showed total or partial rupture of ligaments or tendons. Total ligament or tendon failure was identified at one or more skeletal sites in 54 birds. In two cases, avulsion of the femoral origin of the cranial tibial muscle had occurred. Other findings included degenerative changes in a number of joints but there was no correlation with ligament derangement. Partial or total detachment of the femoral head occurred in 16 birds. The primary lesion was disturbed endochondral ossification and, once detached, the femoral head normally became necrotic. In the reparative phase, 'creeping substitution' was identified.