Lute: I can't answer for wenisrubber, but I get my mice from a local pet store who gets them from www.rodentpro.com (I could order direct but their minimum order is large and their shimmping is expensive)

I use them for two reasons. 1) the mice are always plump and healthy looking. 2) I emailed a bunch of companies when I was looking for a source of frozen feeders and rodentpro emailed me back to assure me that they kill their mice humanely. They were the only company that addressed my concerns at all, and I was satisfied that their mice didn't suffer.