The efficiency of feed utilisation for gain is also reduced under heat stress. It has been reported that body weight gain from 4-8 weeks of age was 1,225 grams at 21ºC, and was reduced linearly to only 1,087 grams at 26ºC. Such a problem comes not so much from temporary exposure to heat as from continuous exposure, as the chickens will have no opportunity to move to more comfortable temperatures. Heat stress does not only affect feed intake and utilisation, but also has negative impacts on the carcass quality.