Wind Air flow and the gas content Vehicle vibrations. Food and water deprivation. If local weather conditions are such that the bird is incapable of maintaining its normal body temperature, it will be thermally stressed. Heat loss within the zone of thermal comfort occurs mainly by sensible heat loss, i.e. by conduction, convection, panting and radiation. The rate of heat exchange is directly related to the temperature differences across a material and thus heat loss or gain may be modified by introducing insulating layers to reduce the thermal gradient.
Plumage provides good insulation but broilers sometimes have poor feathering.
During transportation, flexible behavioral responses are impossible and exposure to certain weather conditions may result in birds suffering or dying from heat or cold stress. Panting adversely alters the microclimate in the crate, making it increasingly difficult for adjacent birds to lose heat. It is therefore essential that adequate air flow is maintained to replenish the air around all birds with cooler, drier air. The rate of heat loss by convection and radiation depends on cooler and drier air. A model of such a transporter was developed at the Roslin Institute in the U.K and it seems to fit the requirements.