Observations on femoral head abnormalities in broilers.

Detachment of the proximal femoral cartilaginous epiphysis was observed in broilers that were being down-graded at slaughter as a result of haemorrhage into thigh musculature. A traumatic aetiology is proposed with injury occurring at catching. Examination of field case material, and birds culled from a commercial flock of the same strain, revealed that physeal lesions are not infrequent in proximal femora. Clefts and areas of matrix necrosis occurred in normal and dyschondroplastic physeal cartilage. Clefts were thought to result from repetitive minor trauma insufficient to cause total detachment of the cartilaginous epiphysis. Total detachment may result from an acute traumatic episode or be a consequence of pre-existing physeal lesions. A traumatic aetiology suggests that in such cases the terms fracture separation or traumatic epiphyseolysis of the cartilaginous epiphysis are more appropriate than femoral head necrosis or degeneration.