Summers hit us hard and birds are no exception to the heat. Birds do not have sweat glands and have their heat managing mechanisms. In general, chickens can withstand the thermoneutral zone of 18 to 28° C. High temperatures above 29°C leads to heat stress. Body temperature for a domestic fowl is between 40°C and 41.7°C. Since the bird’s metabolism is strong, it must be able to lose heat, which it does by radiation, conduction and water evaporation. But, as the bird grows in size, this ratio shifts and radiation of heat through the skin may not be enough to hold the temperature down for the hefty three kg broiler. Hot weather can have a severe impact on poultry performance and heat stress is a major concern during summer.
Heat stress
Birds are ‘heat stressed’ if they have difficulty achieving a balance between body heat production and body heat loss. This can occur at all ages and in all types of poultry.
In the thermoneutral zone, birds can lose heat at a controlled rate using normal behaviour. There is no heat stress and body temperature is held constant. When conditions like the upper critical temperature exceed, birds lose heat actively by panting. Panting is a normal response to heat and is not initially considered welfare.
But as temperatures increase, the rate of panting increases. If heat production becomes greater than ‘maximum heat loss’ either in intensity (acute heat stress) or over long periods (chronic heat stress), birds may die. The body temperature of the broiler must remain very close to 41°C (106°F). If the body temperature rises more than 40°C above this, the bird will die.
Steps to be taken in keeping chickens and feed-in moderate temperature:
Arrangement of roof and side mesh
Fogger and sprinkler
Ceiling fan and curtain management
Free land growing
Feed management:
Give fresh feed from 22nd to 28th day. Feed Control:
Water management and motivator
Medication and other measures during summer