** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** OUR WORK HAS REVEALED THAT EARLY-POST HATCH STRESSOR EXPOSURE CAUSES EPIGENETIC ALTERATIONS IN BRAIN CIRCUITS THAT DIRECTLY AFFECT BEHAVIOR, SPECIFICALLY FEED INTAKE, AND STRESS RESPONSES, IN CHICKENS. WE HAVE SHOWN THAT EARLY-POST HATCH STRESSOR EXPOSURE CAUSES EPIGENETIC MODIFICATIONS, ASSOCIATED WITH INCREASED CORTICOTROPIN-RELEASING FACTOR, THAT LATER AFFECT FEED INTAKE NEURONAL CIRCUITRY WITHIN THE HYPOTHALAMUS. TO OUR KNOWLEDGE THIS IS THE FIRST INSTANCE IN WHICH AN ENVIRONMENTAL STRESSOR HAS CAUSED EPIGENETIC MODIFICATIONS WITHIN A PRODUCTION-IMPORTANT NEURONAL CIRCUIT IN A FARM ANIMAL. THUS, THE PURPOSE OF THE PROJECT PROPOSED HEREIN IS TO ELUCIDATE THE MECHANISM BEHIND HOW EARLY POST-HATCH ENVIRONMENTAL STRESSORS CAUSEEPIGENETIC MODIFICATIONS TO AFFECT POULTRY BEHAVIOR, AND USE THIS INFORMATION TO IDENTIFY MOLECULAR BIOMARKERS FOR CHICK STRESS. WE PROPOSE TO USE SEQUENCING TO IDENTIFY DIFFERENTIALLY-EXPRESSED GENES AND DIFFERENTIALLY-METHYLATED REGIONS IN THE GENOME IN INDIVIDUAL HYPOTHALAMIC REGIONS, AND FIND THE PATHWAYS THAT ARE RESPONSIBLE FOR STRESS AND APPETITE RESPONSES TO STRESSORS. TO DETERMINE WHETHER THE IDENTIFIED PATHWAYS ARE SUSCEPTIBLE TO EPIGENETIC-MODIFYING TREATMENTS, CHICKS WILL BE ADMINISTERED METHYL DONORS OR DNA METHYLATION INHIBITORS PRIOR TO STRESSOR EXPOSURE, AND EFFECTS ON GENE EXPRESSION, DNA METHYLATION, AND FEEDING BEHAVIOR WILL BE EVALUATED. KNOWLEDGE GAINED, WHICH OTHERS MAY USE TO DEVELOP STRATEGIES TO MODULATE FEED INTAKE AND STRESS RESPONSES, MAY REDUCE THE PROPENSITY OF THE ANIMAL TO OVEREAT, IMPROVE ANIMAL WELFARE AND WELL-BEING, AND LESSEN THE NEED FOR FEED RESTRICTION IN BROILER BREEDERS.