I maintain a small mice colony just to have a source of live pinkies and fuzzies when I need them. It's starting to get to the point where I'm culling adults, and I hate, hate, hate cervical dislocation. Would placing a small bit of dry ice in a rubbermaid, and letting it dissolve (or splashing it with a bit of water to speed it along) be an effective and relatively humane way to euthanize the adults I don't need?

Thanks