see www.schlachthof-transparent.org/pages/schlachtprozess/rinderschlachtung.php
If you were born as a pig, you would be lowered in small groups of at least two to eight animals in gondolas or baskets in a 9 m deep pit, which is filled with CO2. Since CO2 causes severe shortness of breath, you would pass out after about 15 seconds with breathlessness and fear of suffocating and gasping for air. Afterwards you would be pulled up again and automatically tilt out of the gondola. Then you would, while hanging, bleed out, by a cut through the carotid artery, which would lead to death at last. The blood withdrawal would have to be done at short notice, because otherwise you would wake up. This is what would happen to you if you were born as a pig and were slaughtered for the consumption of meat by humans.
see www.schlachthof-transparent.org/pages/schlachtprozess/huenerschlachtung.php