Good biosecurity on farms prevents disease outbreaks that cause significant animal suffering, highlighting the overlap between disease prevention and welfare improvement.
Disease outbreaks cause profound suffering: fever, respiratory distress, neurological symptoms, and often death. Mass culling by gassing, shooting or injection during outbreaks, while intended to control spread, causes suffering in healthy animals as well as diseased ones. Investing in biosecurity prevents both disease suffering and culling events. The welfare benefit of disease prevention is enormous relative to its cost.