Published by permission from The Poultry Times. c/o N/A originally printed 4/7/2016.
Written by Gillan Ritchie
GAINESVILLE, Ga. — Summer is a few months away but it is time for poultry producers to watch temperatures and the effects that warmer weather will have on their flocks. Hot weather can affect poultry flocks and how they perform. Birds typically experience heat stress when the temperature rises above 80 degrees F; effects become more apparent when the temperature rises above 85 degrees F. When a bird experiences heat stress, the bird will begin to pant and physiological changes within its body will help eliminate excessive heat. By practicing proper heat management, poultry producers will be able to keep their birds comfortable and maintain growth; hatchability; egg size, shell quality and production. Birds will start to dissipate body heat from the wattles, shanks and the unfeathered areas under the wings when temperatures rise above mid- to upper 90s. Poultry do not sweat and must dissipate body heat to maintain a body temperature of 105°F. Normal behavior, feed intake and metabolism are not altered drastically when the bird maintains its body temperature through heat loss.
Poultry house ventilation helps birds maintain a proper body temperature by sensible heat loss. Methods for sensible heat loss include radiation, conduction and convection, which are effective methods when the temperature ranges from 55 degrees F to 75 degrees F. However, once temperatures rise above 77 degrees F, the method for heat loss shifts to evaporative heat loss. Birds will dissipate body heat by panting, which occurs once temperatures reach 80 degrees F. When a bird pants during evaporative heat loss, the heat is removed through the evaporation of water of the moist lining of the respiratory tract. Panting though, generates more heat, and causes birds to eliminate water from their body. Evaporative heat loss becomes the primary method by which birds regulate their body temperature during the summer months unless proper steps to reduce heat stress are taken. Heat stress can be reduced by maintaining a grass cover around the poultry house to help reduce the reflection of sunlight into the house. The vegetation should also be trimmed to avoid blocking any air movement.
Trees can be planted, but ensure that they are in areas that don’t restrict air movement. Make clean and cool water available to the birds; electrolytes can be added to the water source to help replace those lost during periods of heat stress. Provide adequate ventilation and air circulation for the nesting boxes. To read more about the signs of heat stress, Pennsylvania State University Extension offers more information at http://extension.psu.edu/business/start-farming/news/2014/hot-weather-management-of-poultry.