Pre-slaughter stunning is required in most developed countries for poultry, but stunning effectiveness is highly variable. Understanding what constitutes effective stunning is critical to welfare at slaughter.
Poultry slaughter stunning is a critical welfare intervention that is implemented with highly variable effectiveness across the industry. Water-bath electrical stunning — the dominant commercial method — has significant failure rates: birds that hold their heads up miss the water bath entirely, and current settings that vary by line speed and individual bird conductivity produce inconsistent stunning depth. Birds that regain consciousness between stunning and killing experience the full trauma of throat-cutting while conscious — a severe welfare failure occurring at industrial scale. Controlled atmosphere systems using inert gas or low-oxygen mixtures address these failures by avoiding the handling stress of shackling conscious birds and producing more reliable insensibility. The welfare case for CAS adoption is strong and acknowledged by welfare science; cost and infrastructure barriers slow adoption.