Research at North Carolina State, Oklahoma State and The University of Georgia has shown that birds are able to adjust to heat if they are allowed to become accustomed to it gradually. Recent studies at Virginia Tech have shown that if birds are subjected to a brief heat stress early in life, they are much more capable of withstanding heat stress later in production. There is much we don't understand about how birds acclimate or why early exposure reduces future susceptibility to heat. As more is learned about these mechanisms, we will certainly be better able to reduce heat losses. Fasting poultry during hot weather also helps them withstand heat stress.
Sufficient water is absolutely essential during hot weather.
Watering systems must be in peak condition. If nipple drinkers are being used to grow large birds, pressure regulators must be adjusted to supply maximum water. If birds can get water on their combs and wattles, evaporation does much to cool them. Increasing floor space per bird during hot weather is necessary in houses with marginal ventilation and evaporative cooling systems. Reducing bird numbers reduces the amount of heat produced and the amount of heat the ventilation system must remove from the house.