Increasing concerns over antibiotic use in food animals and the emergence of antibiotic-resistant pathogens led to the FDA directive curbing AGP use in poultry production. Thus, there is a critical need for an effective alternative to promote poultry health and performance. Several researchers have demonstrated the potential for dietary supplementation of probiotics in day-old chicks on improving growth performance in broiler chicken. However, the period of embryonic and neonatal development accounts for almost 50% of the productive life of modern broilers and is critical to attaining quality performance at marketing. Hence, the overall goal of this study is to promote embryonic growth as a means to improve post-hatch growth in broilers.The specific objectives of this study are:1. To determine the effects of early probiotic administration on muscle growth and performance in broiler chickens.2. Identify candidate genes and pathways mediating the beneficial effects of probiotic supplementation on muscle growth in broilers.