Modeling hen house ventilation options for cage-free environment: Two-dimensional case

Poultry facilities are going through perhaps the largest evolution in design due to demands for a wide range of building configurations to accommodate cage-free, enriched cages, and organic standards. An Egg Industry Center project is developing practical recommendations for modern hen housing ventilation systems by working with commercial builders and poultry company management. The method for evaluation is simulation of poultry house environment via Computation Fluid Dynamics (CFD). This paper outlines the development of a two-dimensional model of a commercial-scale floor-raised cage-free hen house as a first step in documenting current conditions and exploring options for ventilation improvements. A thin slice of the building cross section was modelled with realistic geometry and representative hen shapes with heated surface areas. Of concern was that the ventilation system components of this thin two-dimensional slice were not representative of real conditions. Uneven airflow resulted from limitations of the two-dimensional simulation because the complete ventilation flow field could not be fully modeled in a 2-D slice. In spite of the limitations of the 2-D simulation, modeling of hen house and individual birds’ geometries provided fundamentals for further investigation, such as a fully three-dimensional CFD simulation. In addition, an extended computational domain enabled investigation of the relationship between ventilation inside the hen house and the outside atmosphere. For animal welfare concerns and disease spread control, deeper and more realistic investigations are being conducted in three-dimensions based on the preliminary findings of this 2-D simulation.