How avian influenza outbreaks affect farmed poultry welfare, the ethics of mass culling, and what better biosecurity looks like.
Avian influenza creates some of the most acute welfare crises in modern farming. When HPAI enters a flock, disease progression is rapid, severe, and fatal. The response is typically mass culling of all birds on an affected premises, sometimes tens of millions of birds at a time. The welfare of culling methods is highly variable: carbon dioxide or carbon monoxide gassing, if properly administered, can be relatively humane, but ventilation shutdown with or without heat has been widely criticized as causing prolonged suffering. The welfare implications of outbreak response require urgent policy attention.