Mechanical harvesting machines for broiler chickens represent a welfare improvement over manual catching for some operations, but introduce their own welfare risks that require careful monitoring and management.
Mechanical harvesting welfare must be assessed comparatively against manual catching rather than against an ideal of zero stress catching. Well-operated mechanical harvesters reduce injury rates, physical handling stress, and the welfare variability introduced by individual catcher skill and fatigue. However, machines are not inherently low-welfare: poor maintenance, inappropriate bird density during harvesting, and inadequate monitoring can cause catching injuries. The key welfare variables are machine maintenance standards, operator certification, monitoring of injury rates, and scheduling harvesting at appropriate times. Outcome monitoring - wing fractures and bruising at slaughter - provides objective welfare data.