Avian influenza outbreaks have led to the culling of hundreds of millions of poultry worldwide, with the welfare of birds during culling varying significantly by method.
Mass culling of poultry during disease outbreaks represents one of the most acute large-scale welfare challenges in animal agriculture. The scale of outbreaks makes individual humane slaughter impractical, requiring whole-flock methods that vary greatly in humaneness. Ventilation shutdown — closing all air supply to a building — causes slow death from overheating and suffocation and is condemned by major veterinary organisations as inhumane. Whole-house gas filling systems cause rapid unconsciousness and are vastly more humane alternatives, though their deployment requires advance preparation.