Different commercial broiler crosses have different susceptibilities to leg weakness.

A trial was conducted to investigate the susceptibility of different genotypes of broilers to leg weakness. Four crosses of commercial broiler lines were assessed. Birds were reared on commercial diets at commercial stocking densities. Indices of leg weakness examined included: walking ability, tibial dyschondroplasia (TD), foot pad burn, hock burn, and angulation of the hock joint. Body weight and feed efficiency were also measured. There were small differences in BW and feed efficiency among the commercial crosses; however, there were large differences in some of the indices of leg weakness among the crosses. Three crosses had similar prevalence of TD; one cross had much less TD than the others. There were large differences in walking ability among crosses. There were also differences among crosses in the prevalence of foot pad and hock burn and angulation of the hock joint. Adjusting the observations for differences in BW did not substantially alter the findings. There were differences among genotypes regarding the correlation coefficients between walking ability and BW, walking ability and hock burn, and TD and BW. It was concluded that there were large differences in some important traits associated with leg weakness among the commercial line crosses.