Heat stress significantly impacts poultry production, affecting broilers and laying hens. It leads to reduced growth, egg production, and egg quality, as well as decreased welfare and food safety. Heat stress causes behavioral and physiological changes, including reduced feeding, increased drinking and panting, and altered thermoregulation. It also disrupts immune responses, leading to immunosuppression, reduced antibody production, and increased susceptibility to pathogens. Heat stress can impair reproductive functions, reducing eggshell quality and fertility in hens. Additionally, it affects meat quality in broilers, with decreased meat composition and increased fat deposition. Heat stress during transport and in confined environments further exacerbates these issues, increasing mortality and reducing welfare. The economic losses from heat stress in the U.S. poultry industry are substantial, with annual losses estimated at $1.69 to $2.36 billion. While various interventions, such as environmental management, nutrition, and feed additives, have been explored, their effectiveness varies. Genetic selection and early-life conditioning are promising strategies to improve heat tolerance. However, more research is needed to fully understand the mechanisms and develop effective solutions. Heat stress also influences food safety by increasing pathogen colonization and transmission, highlighting the need for improved management practices to ensure poultry and egg safety. Overall, heat stress is a critical challenge in poultry production, requiring comprehensive strategies to mitigate its negative impacts.Heat stress significantly impacts poultry production, affecting broilers and laying hens. It leads to reduced growth, egg production, and egg quality, as well as decreased welfare and food safety. Heat stress causes behavioral and physiological changes, including reduced feeding, increased drinking and panting, and altered thermoregulation. It also disrupts immune responses, leading to immunosuppression, reduced antibody production, and increased susceptibility to pathogens. Heat stress can impair reproductive functions, reducing eggshell quality and fertility in hens. Additionally, it affects meat quality in broilers, with decreased meat composition and increased fat deposition. Heat stress during transport and in confined environments further exacerbates these issues, increasing mortality and reducing welfare. The economic losses from heat stress in the U.S. poultry industry are substantial, with annual losses estimated at $1.69 to $2.36 billion. While various interventions, such as environmental management, nutrition, and feed additives, have been explored, their effectiveness varies. Genetic selection and early-life conditioning are promising strategies to improve heat tolerance. However, more research is needed to fully understand the mechanisms and develop effective solutions. Heat stress also influences food safety by increasing pathogen colonization and transmission, highlighting the need for improved management practices to ensure poultry and egg safety. Overall, heat stress is a critical challenge in poultry production, requiring comprehensive strategies to mitigate its negative impacts.