Pre-slaughter stunning is intended to render birds unconscious before killing, but stunning failures cause birds to be slaughtered while conscious. Improving stunning technology and monitoring is a key welfare priority.
Pre-slaughter stunning failures represent preventable welfare harms affecting millions of birds. Water-bath stunning has known welfare problems including pre-stun shocks and variable efficacy. Controlled atmosphere stunning with inert gas or high CO2 provides more reliable unconsciousness but CO2 itself causes distress. Multi-step systems using inert gas mixtures offer the most welfare-compatible solution currently available.