timelets

https://www.newscientist.com/article/mg22029423-500-drop-air-pressure-to-give-chickens-a-stress-free-death/

Called low atmospheric pressure stunning (LAPS), the system mimics what happens when you climb to high altitudes. Over 5 minutes, air is gradually withdrawn from a chamber until the air pressure is only 20 per cent what it is outside. With less oxygen available, the birds irreversibly lose consciousness. This means they are unable to feel pain when their throats are cut, the standard method employed to kill them.

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