** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** IMPROVING BROILER MEAT PRODUCTION TO MEET CONSUMER DEMAND HAS RESULTED IN THE SHORTENING OF THE TIME REQUIRED FOR MODERN BROILERS TO REACH MARKET WEIGHT. DUE TO THIS, THE PERIOD OF EMBRYONIC DEVELOPMENT CONSTITUTES TO ABOUT 30% OF A BROILER'S LIFE. FURTHER, OPTIMUM GROWTH DURING THE EMBRYONIC PERIOD AND IMMEDIATELY PRIOR TO HATCH IS IMPORTANT TO CHICK PERFORMANCE IN REACHING MARKET WEIGHT. HENCE SUPPORTING THIS CRITICAL EMBRYONIC PERIOD IS CRITICAL TO PROMOTE OVERALL BIRD HEALTH AND PRODUCTION. ALONG THESE LINES, PROBIOTICS ARE ONE OF THE MOST COMMON GROWTH PROMOTERS EMPLOYED IN BROILER PRODUCTION. HOWEVER, THEY ARE PRIMARILY USED AS A FEED SUPPLEMENT POST-HATCH AND THEIR EFFECT ON EMBRYONIC GROWTH HAS NOT BEEN STUDIED. GIVEN THEIR BENEFICIAL ATTRIBUTES, SUPPLEMENTATION OF PROBIOTICS TO GROWING EMBRYOS COULD BE A POTENTIAL APPROACH TO PROMOTE GROWTH AND PERFORMANCE IN BROILERS. TOWARDS THIS, OUR PREVIOUS RESEARCH DEMONSTRATED THAT PROVIDING PROBIOTICS TO GROWING EMBRYOS NOT IMPROVED EMBRYO GROWTH BUT ALSO PROMOTED BODY WEIGHT GAIN AND MEAT YIELD IN CHICKENS. FURTHER, WE ALSO OBSERVED THAT PROBIOTICS ALSO IMPROVED HATCHABILITY AND HATCHLING QUALITY. ONE OF THE KEY DETERMINANTS IS THE ENERGY STATUS OF THE EMBRYOS. ADDITIONALLY, THE IMPROVEMENT IN GROWTH CAN BE DUE TO IMPROVED INTESTINAL FUNCTION INCLUDING CECAL MICROBIAL ACTIVITY. THEREFORE, TO BETTER UNDERSTAND HOW PROBIOTICS PROMOTE GROWTH, IN THIS PROJECT WE WILL DETERMINE PROBIOTIC EFFECT ON THE GLUCOSE AND GLYCOGEN RESERVES, INTESTINAL DEVELOPMENT AND FUNCTION AND CECAL MICROBIOME IN THE EMBRYO AND CHICKS. IT IS EXPECTED THAT THIS STUDY WILL HELP DEMONSTRATE THE POTENTIAL FOR TARGETING BROILER EMBRYOS TO IMPROVE PRODUCTION IN THESE BIRDS. OVERALL, USE OF PROBIOTICS TO IMPROVE GROWTH AND THEIR APPLICATION ON EGGS MAY SERVE AS A NOVEL AND EFFECTIVE STRATEGY FOR RAISING.