** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** BROILER CHICKEN MEAT IS BY FAR THE MOST CONSUMED MEAT AMONG US CONSUMERS. THUS, THE GOAL OF THIS PROJECT IS TO DETERMINE THE ROLE OF HATCHING EGG INCUBATION TEMPERATURE CONDITIONS IN THE DEVELOPMENT OF A MEAT QUALITY DEFECT CALLED WOODEN OR WOODY BREAST (WB), WHERE AFFECTED CHICKEN MEAT IS ABNORMALLY HARD TO THE TOUCH AND OFTEN RESULTS IN A NEGATIVE EATING EXPERIENCE FOR CONSUMERS. THIS COSTLY MEAT QUALITY DEFECT PLAGUING THE GLOBAL COMMERCIAL POULTRY INDUSTRY MANIFESTS IN THE FASTEST-GROWING, HEAVIEST-MUSCLED BROILER CHICKENS AND COSTS COMMERCIAL US BROILER PRODUCERS AT LEAST $200 MILLION PER YEAR. OUR PRELIMINARY WORK SUGGESTS THAT BROILER CHICKENS AFFECTED WITH WB HAVE ABNORMALITIES IN THEIR MUSCLE SATELLITE/STEM CELL POPULATIONS, WHICH ARE ESSENTIAL FOR MUSCLE GROWTH. IMPROPER HATCHING EGG INCUBATION TEMPERATURES ARE KNOWN TO NEGATIVELY IMPACT MUSCLE STEM CELL FUNCTIONALITY AS WELL AS BROILER GROWTH PERFORMANCE. TO DATE, POST-HATCH BROILER NUTRITION AND MANAGEMENT STRATEGIES HAVE BEEN UNSUCCESSFUL IN ELIMINATING WB. THEREFORE, THIS PROJECT IS DESIGNED TO ASSESS THE EXTENT TO WHICH HATCHING EGG INCUBATION CONDITIONS ARE NEGATIVELY IMPACTING THE DEVELOPMENT OF CHICKS SUCH THAT THEY DEVELOP COSTLY WB MYOPATHY. WE WILL USE A COMBINATION OF EXPERIMENTAL APPROACHES TO INVESTIGATE THE FUNCTIONALITY OF THESE ESSENTIAL STEM CELLS IN BROILER CHICKENS AND DETERMINE IF IMPROPER INCUBATION TEMPERATURES DURING BOTH EARLY AND LATE-STAGE HATCHING EGG INCUBATION ARE CONTRIBUTING TO THE DEVELOPMENT OF THE WB MEAT QUALITY DEFECT. SUCCESSFUL ACHIEVEMENT OF OUR PROJECT WILL NOT ONLY PUSH US TOWARD ELIMINATING THIS FOOD QUALITY PROBLEM AND THE ECONOMIC LOSSES FOR MEAT PRODUCERS BUT SIMULTANEOUSLY INCREASE OUR KNOWLEDGE OF BASIC SKELETAL MUSCLE GROWTH MECHANISMS WHICH WILL FURTHER ENHANCE OUR ABILITY TO SUSTAINABLY PRODUCE ENOUGH HIGH-QUALITY, NUTRITIOUS CHICKEN MEAT PRODUCTS TO MEET GROWING CONSUMER DEMAND.