One of the keys to understanding poultry house ventilation during cold weather is remembering one simple rule: In order for air to hold moisture, energy or heat is required. The warmer the air, the more moisture it can hold. For example, the air contained in a 400' broiler house can hold up to 66 lbs of water at 40°. But, if the same amount of air were heated to 70°, the amount of moisture the air can hold increases to 184 lbs.