Layer flocks are reared for egg production. In the present scenario, climate change is having important effect on agriculture and farm animal production. Rise in environmental temperature is of major concern since it leads to heat stress. Increase in demand for chicken products protein supply also, puts challenge to the environment. Technologies are being developed for the intensification of poultry production. We have to still develop new technologies which will be viable and suit according to the climate change and become resilient to heat stress. Beyond the thermoneutral zone or at high ambient temperatures the egg production of layer decreases necessitating to manage heat stress properly. The decrease in egg productivity is dependent on different variables. In the present review, various physiological parameters in layers have been discussed which are being affected by heat stress, either naturally or under artificial conditions. Based on the physiological variables mentioned, other variables have to be explored, which if managed, may result in better egg production.
Key words: Layers, Egg Production, Heat Stress, Hormones Egg Shell Quality, Oxidative Stress