Egg Industry Center

Ventilation Shutdown Study

Modeling of ventilation shutdown (VSD) to help stop HPAI virus transmission


One of the key lessons learned from the HPAI outbreaks was the imperativeness of quickly stopping the virus transmission by depopulating the infected flocks as soon as possible. The U.S. Department of Agriculture now recommends depopulating the inflected flocks within 24 hours of positive confirmation. 

With the number of birds involved in today’s commercial layer facilities and the absolute necessity of swift depopulation, ventilation shutdown (VSD) offers an effective euthanasia solution in emergency situations.  However, proper procedures must be followed to ensure its success and the well-being of the animals involved. The purpose of this study was to use existing data to model the needs for proper depopulation using VSD. The goal was to provide information that could act as a guideline for the industry should this need arise in a future HPAI outbreak.


The study found that a critical component for successful VSD is the proper distribution and ample supply of supplemental heat. The research team developed a computer model that simulates the indoor environment upon VSD and the supplemental heat capacity required to reach and maintain the target environment for different housing styles, production stage of the birds, and a range of weather conditions. This information has been adopted, and used, by the USDA and egg producers. When available, field data are being collected and used to continue to validate and refinement the VSD model.

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