Absolutely nothing peaceful about it. Pigs in UK are killed with CO2 and it’s harrowing. The only advantage is that slaughterhouse workers don’t need to look their victims in the eyes while it happens. The pigs get lowered into a gaschamber where they proceed to shit themselves and scream their lungs out while fighting for up to 3 minutes of their miserable lives. You can find a pretty recent documentation about it called Pignorant by vegan activists who infiltrated those facilities. They’ve also protested in front of the HQs of those companies (e.g. Pilgrims) by playing back the audio from the gas chambers.
I’m not into that topic. According to a quick search the exhaust fumes method is working because of Carbon Monoxide (CO) and not Carbon Dioxide (CO2). Wasn’t there a redditor who did not recognize he was killing himself with CO and other redditors saved his life?
I’ve also found a pretty repulsive study done on piglets about the ideal gas for euthanization. It found a 2-step procedure with N2O (Nitrous Oxide) + O2 (Oxygen) as an anesthetic for 12 min followed by killing via CO2 was the most stress-free method.
The activists are protesting against the CO2 method in the UK currently. And I hope the management of the respective companies get public hell for it. I don’t know if it’s used in other countries too.