Broiler Welfare at Slaughter: Controlled Atmosphere Stunning

Controlled atmosphere stunning (CAS) is increasingly used as a more humane alternative to electrical waterbath stunning for broiler chickens at slaughter.

Key Facts

Waterbath stunning can fail if birds miss the stun - leaving them conscious during slaughter
CAS using high concentrations of inert gas or CO2 achieves stunning before any handling stress
Birds enter CAS systems in their transport crates, avoiding inversion handling that causes wing dislocations
High-CO2 CAS causes aversion - low-oxygen systems using argon or nitrogen cause less distress
CAS is increasingly required by higher welfare certification schemes for poultry

Welfare Considerations

Slaughter method welfare is a high-stakes welfare decision affecting billions of broiler chickens annually. Electrical waterbath stunning has known failure rates from birds dodging the stun, leaving them conscious and in pain at slaughter. Controlled atmosphere systems, while involving a period of exposure to the stunning gas, avoid the acute handling stress of inversion and have lower failure rates. The welfare-optimal CAS system uses low-oxygen gas rather than high CO2, which causes aversion. Consumer demand for higher welfare poultry that specifies humane slaughter methods drives adoption of better systems.

What You Can Do

Choose poultry products from producers using CAS with low-oxygen gas systems
Ask retailers about slaughter methods in their poultry supply chains
Support campaigns for higher welfare slaughter standards in poultry certification
Reduce poultry consumption to support better welfare standards broadly