Improve the accuracy of chicken leg disease assessment by combination of gait score and X-ray scan

With the overselection of broiler body weight (BW) and breast muscle weight (BMW), the incidence of leg disease has been gradually increasing, which has seriously affected the welfare and industrial economic development of broilers. In this study, we used gait score and X-ray to evaluate the leg health of fast large white-feather broiler chickens at the age of 6 to 7 wk. The combined use of the 2 methods improved the detection rate and accuracy of diagnosing chicken leg disease. Moreover, more than 70% of chickens with abnormal gait scores also appeared abnormal on X-ray. At the same time, the 40-day BW, 42-day BMW, 28- to 40-day body weight gain (BWG) and tibial bone strength (BS) of the abnormal broilers were significantly lower than those of normal chickens. The 28- to 40-day feed conversion rate (FCR) significantly increased relative to normal chickens (P < 0.05). The comprehensive application of this method would be more suitable for evaluating of commercial broiler leg diseases, and providing a more complete set of in vitro evaluation criteria for broiler leg diseases.