Another 'yes' for hate PETA here - but on the CO2 thing, if you are doing it properly, aka slowly you are basically making the mice, bunnies, rats 'drunk' through the decrease in oxygen. I watched 5 rabbits put down together over 15 mins by CO2 - some simply lay down and looked calm, one quickly started humping another rabbit. Happy way to go don't you think? This was with a canister of CO2 and a pressure guage.