Gass Euthanization for Rodents

[Minkness]

I plan on getring several snakes in the future and woul like to breed my own mice or rats. I have had both as pets in my past, so know about their care. What keeps preventing me from commiting is that I won't feed live, would be unable to break their nexks, or cause other physical harm to them. I have read alot about the gassing technique but not sure where people get it or any thing like that.

So...how and where do you get the gass? What kind is it? How do you make the 'gas chamber'?.... (I feel like a nazi asking these questions x.x)