In the UK, the practice of gas stunning for pigs, chickens, turkeys, and others, is still backed by many organisations as being a 'humane' slaughter with minimal suffering. If you view the many videos on youtube of this practice, you can see that this is completely incorrect.
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The practice involves using a gas mixture to cause animals to suffocate into unconsciousness before they have a knife drawn across their throat. This may cause immense pain and suffering to the animal as a release of acid is initiated inside the animal, causing the sensation of burning throughout the animal's body. How can anyone say this is a moral practice?