A chicken or poultry grow out facility utilizes a ventilated floor assembly including a ventilated floor through which liquid and gas can flow, but which retains manure and other solids deposited thereon, and a bottom air plenum underneath the ventilated floor which is vented to the poultry growth chamber. A liquid and vapor barrier sheet preferably covers the ground surface underneath the floor assembly which together insulate the high temperature of the grow-out facility from the heat sink effect of the lower temperature ground. Conventional tunnel ventilation of the chicken or poultry house through the ends of the house creates a negative pressure inside the growth chamber and air plenum relative to the outside environment. As a result of this tunnel ventilation and negative pressure, moisture in the manure evaporates into the air in the growth chamber and into the bottom air plenum to effectively dry the manure retained on the floor and reduce ammonia formation and bacteria growth.
