I havent tried pre killed yet, im afraid im gonna kill it he wont take it and that would just be a waste of a rat, iv stunned the live rat and he took it right away... iv tried taking a rat out of the freezer thawing it for about 4 hrs at room temp and then put it under a heat lamp to warm it up before offering... also iv tried taking the rat directly from the freezer put it in a zip lock sandwich bag and run it under really hot water for bout 10 mins till its thawed and warm before offering...he eats in a little tub usually but iv tried his cage, the tub, the tub in a dark place??? all No goes