Do NOT put a rodent in the microwave, nor should you leave it out over night. As the rodent thaws, the decomposition process, so by time it is good and thawed, it will also be fairly spoiled. Plus, a small rat doesn't take very long to thaw at all. Put it in a ziplock bag, put it in some hot water from the sink for a half hour to an hour. Right before I put the rat in with the snake I warm the water up for a minute or so to warm the rat up a little. You don't want it hot, but warm to the touch. My bp won't strike or eat in front of me so I just put it in his hide with him.