i know that they get the mice from a breeder but i'm not sure if they come frozen or if they do it themselves. i think they use CO2 and gas them, but i'm not absolutely sure. i'm not totally sure that what i'm seeing is actually pee, but that is what it looks like. like their fur is dirty as if something got on them before they were frozen. if they were just put in the freezer and killed that way (yes i know that is terrible, but i know that some places unfortunately do it) would they pee and get funky that way? i definitely don't want to buy from a store that does it that way.