Poultry slaughter welfare is determined primarily by stunning effectiveness, shackling stress, and the time between shackling and stunning — areas where significant welfare improvements remain to be implemented.
Poultry slaughter involves more individual animals than any other slaughter operation, meaning welfare improvements in this sector have the largest numerical impact on animal suffering. Shackling conscious birds causes distress through inversion, struggling, and physical stress; electrical stunning risks mis-stun at the scale of millions of birds. Transition to multi-phase controlled atmosphere systems using nitrogen or argon represents the highest-welfare approach currently available.