i know that in Germany rhodents are available live as well as frozen thawed, and people feed their snakes live as well as frozen thawed. And its legal.
There are laws against inhumane killing of vertebrates, which includes of course mice as well as snakes and almost all other pets. I guess feeding rhodents to snakes just doesnt fall under what would be considered inhumane. when it comes to other animals that dont kill by quickly disrupting the blood stream, like snakes do, but that basically rip their prey into pieces, its a different story. i dont think live feeding of sharks or lions or hyenas or birds of prey or crocodiles is done in Germany.
Many snake keepers in Germany, and that includes big breeders, actually prefer to feed live.