Humane methods for prekilling feeders

[Serpens]

I've decided to do the research now, partially because I'm interested, but also because I've heard different things. I know that CO2 is the most humane way to kill rodents, and eventually, when my collection gets big enough to warrant a massive rodent room, that's the way I want to go. I'm curious about how to set up a CO2 euthanizing system. Is there anywhere I can go for that kind of information?

Also, I was wondering about small scale rodent breeding, and the most humane way to euthanize the rodents. I've heard of dislocating the neck, or stunning the animals on a table, but was wondering how this worked if you were feeding adult rats. I'm not big on the thought of hurting these animals any more than they need to be. Any thoughts? If anyone has any other suggestions, I'd also love to hear them as well.

Thanks in advance,
Serpens