Global climate change is accelerating at an unprecedented rate, and the consequences of global warming are expected to worsen. Many heat waves have recently hit various parts of the world, causing major losses in livestock, particularly in the poultry sector, resulting in massive mortalities and catastrophic economic losses. Therefore, the current review sheds light on the effects of heat stress on the poultry industry, and discusses the factors relevant to these harmful effects on behavior, bone development, blood chemistry and physiological changes, pathogenesis, and immune responses. Potential methods to ameliorate the heat stress response in birds, with particular reference to the role of probiotics in controlling such problems, is further discussed.