Effect of unilateral weight-bearing on pelvic limb development in broiler fowls: morphological and radiological findings.

Twenty-five broiler chickens, which habitually adopted a unilateral weight-bearing stance, were studied. In all cases the contralateral limb was held free of the ground, normally as a result of gross valgus angulation of the intertarsal joint. The left pelvic limb was more frequently weight-bearing than the right which suggests that a pattern of limb dominance may occur in broiler fowls. Metaphyseal lesions, suggestive of dyschondroplasia, were more common in the load-bearing limb. This suggests that altered load-bearing or posture can initiate or exacerbate dyschondroplasia in susceptible birds. The load-bearing limb also showed altered patterns of bone torsion. These findings are similar to those observed in induced physeal (growth plate) osteochondrosis in mammals and the pathogenesis of lesions is likely to be similar.