I've done it before with mice and we've had pet rats (just one at the moment), and I can tell you that mice are 42 times stinkier than rats and I won't be having them in my house again (not voluntarily, anyway). It's not difficult. Basically if you leave a sexually mature male in with one or more sexually mature females for 24 hours, odds are very good you'll end up with some pinkies in da hizzouse. Steelsack does it; I believe Jeanne does it. I think someone else does as well but it's not coming to mind right now who that would be.