Therefore, in this study, l-carnitine was injected into the amnion of broiler breeder eggs on d 18 of incubation,at concentrations similar to and higher than those used by Zhai et al. (2008a), to determine if exogenous supplementation of l-carnitine to the embryo would affect hatchability and the subsequent grow-out performance and slaughter yield of broilers through 47 d of posthatch age.