well the only reason is because they havent had any frozen ones for the past 2 weeks and he ate last week so im sure he is hungry. But another reason i like this idea better is because my g/f is totally grossed out by the mice in the freezer lol. and this way i can just go to the pet shop and get a mouse "its only 10 minutes away". but i like the pre-killed idea any suggestions how to do it without making a mess?