Skeletal growth of commercial poultry species.

There have been significant increases in growth and development of commercial broilers, turkeys, and ducks. The large decline in days to market and disproportional increases in breast yield have contributed to greater incidences of various skeletal anomalies. Across all three species, tibial dyschondroplasia is observed about half-way through the growing period (50%), but in each case the birds have achieved 40% or less of their final BW. Relative tibia development (length and width) is significantly slower in broilers compared with turkeys and ducks, which suggests a greater susceptibility to biomechanical problems, the end result of which is abnormal long bone development. There are relatively few studies that have addressed changes in the femur as well as the tibia. There are indications that mineralization rates and other aspects of femur development occur more slowly than what is observed for the tibia. In this regard, the femur may be the weak link with respect to long bone developmental abnormalities. Nutrient restriction during short periods of the growout has proven to be an effective way of decreasing leg abnormalities. In all cases, however, there are corresponding declines in BW at normal market ages and associated declines in absolute breast muscle development. In the future, however, these fractional losses in measures of carcass yield may still be economically advantageous compared with the cost of increased leg problems under field conditions.