Heat stress in laying hens is prompted by combinations of
environmental temperature and humidity that prevent the
bird’s thermoregulatory process from effectively dissipating
the heat produced during metabolism [32]. High environmental
temperature is the major problem faced by laying
hens as well as poultry farmers usually in summer months.
The ideal temperature for laying hens is about 20°C [21].
Heat stress begins when the ambient temperature climbs
above 25°C and is readily apparent above 30°C. Heat stress
in laying hens reduces live weight gain, feed intake, feed
efficiency, production and quality of eggs and increases mortality
[4, 7].