BONE DEFORMITY IN BROILERS

Angular bone deformities occur when the legs become bowed in or out, and may even be twisted. This problem is the most frequent cause of lameness in broiler chickens and possibly accounts for 60% of the skeletal disease in chickens. Angular bone disorder can be observed in the flocks from as early as 6 to 8 days old resulting in crippled birds that are unable to reach the feed or water. As the flock ages these birds are more easily identified since they are much smaller and have not developed as well as the rest of the flock. Some birds will die from hunger and other may be condemned due to atrophy of the muscles in the affected legs. Other problems associated with the legs such as Tibial Dyschondroplasia, can be observed in chickens as late as 4 weeks of age. The weight of the bird compresses the legs causing painful lameness. Up to 30% of the flock can be affected; however, most birds show no clinical signs of the disorder. Both Angular bone deformity and Tibial Dyschondroplacia have been associated with rapid growth rate because the birds gain weight at a faster rate than the skeletal structure is able to mature. 

Slowing the growth rate during the first 1 to 2 weeks by reducing feed intake can reduce the incidence of leg problems in a flock; however, this could lower dress weight at slaughter.

Increasing the ratio of Calcium:Phosphorus in the diet have shown to reduce the incidence of leg problems in flocks. Mechanical trauma associated leg problems is more prevalent in fast growing chickens. Specifically handling the birds during the catching can result in femoral head necrosis whereby the head of the femur ruptures causing hemorrhaging. Upon arrival at the processing plant these birds will be found in the cages either dead or dying. This situation can be minimized with the use of the new reaping machines which remove direct human contact with chickens during the clearing out process.