The poultry industry has changed a lot over the last ten years. Nowhere is this change more evident than in the houses now used to grow birds. Concepts such as tunnel ventilation, radiant brooders, and fogging pads were practically unheard of ten years ago. Now they are practically the norm. We have gone from a situation where side wall curtains were the primary method of ventilating a poultry house to today where in many instances the curtains are just there in case of a power outage or to air ...out the houses between growouts.