Numerical Simulation of Airborne Disease Spread in Cage-Free Hen Housing with Multiple Ventilation Options

Abstract

The current ventilation designs of poultry barns have been present deficiencies with respect to the capacity to protect against disease exposure, especially during epidemic events. An evolution of ventilation options is needed in the egg industry to keep pace with the advancing transition to cage-free production. In this study, we analyzed the performances of four ventilation schemes for constraining airborne disease spread in a commercial cage-free hen house using computational fluid dynamics (CFD) modeling. In total, four three-dimensional models were developed to compare a standard ventilation configuration (top-wall inlet sidewall exhaust, TISE) with three alternative designs, all with mid-wall inlet and a central vertical exhaust. A one-eighth scale commercial floor-raised hen house with 2365 hens served as the model. Each ventilation configuration simulated airflow and surrogate airborne virus particle spread, assuming the initial virus was introduced from upwind inlets. Simulation outputs predicted the MICE and MIAE models maintained a reduced average bird level at 47% and 24%, respectively, of the standard TISE model, although the MIRE model predicted comparable virus mass fraction levels with TISE. These numerical differences unveiled the critical role of centrally located vertical exhaust in removing contaminated, virus-laden air from the birds housing environment. Moreover, the auxiliary attic space in the MIAE model was beneficial for keeping virus particles above the bird-occupied floor area.

Modeling the impact of optimized airflow and sick pen management on the spread of infectious diseases in swine barns

“…Over the past decades, computational fluid dynamics (CFD) has become a reliable and widespread toolset to assess the influence of ventilation systems on the transmission of airborne pathogens released from bio-sources (Chen et al, 2022; La & Zhang, 2019; Lipinski et al, 2020; Motamedi et al, 2022; Yang et al, 2015). However, the combined effects of a ventilation system and sick pens on barn-level disease dynamics remain unclear.…”