Pre-slaughter stunning renders animals unconscious before killing, preventing the pain of a conscious slaughter cut. Most countries require stunning, but religious exemptions permit non-stun slaughter for Halal and Kosher production.
The welfare concern with non-stun slaughter is that conscious animals may experience pain and distress from the throat cut before losing consciousness. The duration of consciousness after the cut varies by species, cut quality, and individual animal, making consistent welfare outcomes difficult to guarantee. Many religious authorities have concluded that pre-slaughter stunning is compatible with religious law, and some countries (including New Zealand) require stunning for all animals including religious slaughter. This remains a sensitive balance between religious freedom and animal welfare obligations.