Hybrid-Positive Pressure System: A New Design Concept

Most poultry houses are designed using a negative pressure ventilation program, but free-range facilities require a different approach. Because free-range farms must provide outside access for birds, pop-doors are built into the walls. These doors are often required to be open for long periods, if not continuously, when birds are present.

With negative pressure ventilation, pop-doors act as air inlets, creating cold drafts along the floor during winter. This results in wet litter near the doors and uneven house temperatures. To solve this, houses can be designed using a hybrid ventilation scheme. This design combines natural or negative ventilation with a positive pressure design to accommodate free-range birds in all seasons.

The key to successful positive pressure design is the use of a centrifugal mixing fan. Our Z-Pro™ Hemisphere®, the newest addition to the Hemisphere line, works in any floor bird application. The fan’s patented design pulls air—from above and below—into its center, where it’s mixed and pushed out toward the sidewalls. This creates a constant, slow-moving air current along the walls and floor of the bird space.

The end result is an ideal bird environment: a uniformly well-ventilated, comfortable house that balances bird comfort, consistent temperatures, and litter quality.