Keepers of poultry in back yard flocks or in commercial venutres need to look out for the effects of heat stress on chickens. Smallholders and small farmers are already seeing that climate change increases their challenges.
The warnings of environmental scientists of the effects of climate change are rapidly becoming a reality. Areas of southern Africa are being subjected to more frequent dry spells and droughts. In some areas the rising temperatures are here to stay, while in other areas there is greater temperature variability than before. Seasons are changing in length, rainfall distribution is less predictable and wind speeds are increasing.
All of these changes have a negative impact on poultry production. Climate-induced heat stress is having a marked effect on poultry productivity, particularly in tropical climates.
Heat stress has an impact on chicken welfare and production by altering the natural body temperature of chickens. In the adult chicken the variability ranges between 40.6° and 41.7°C. Chickens do not have sweat glands and control their temperatures through other means.
Effect of heat stress on poultry production
Heat stress leads to chickens taking in less feed and a drop in feed conversion efficiency. They tend to lay fewer eggs and smaller eggs. There has been a rise in poultry deaths.
Heat stress effect on behavioural activities
The chickens spend more time drinking water and panting with open mouth. They flap their wings to help to cool themselves. They have less energy to move or walk, so they spend more time lying down and resting.
Reproduction is affected
The hens’ reproductive efficiency and hormone production is affected. Farmers are seeing reduced fertility in cocks.
Effect of heat stress on physiology and immunoglobulin
The chickens’ pulse rate is higher. Their immune systems are also negatively affected. Heat stress affects the oxygen levels within the blood.
Effect of heat stress on carcass characteristics
Stressed chickens result in lowered carcass weight. It also affects egg and meat quality.
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