Well, the one time I had thawed out 2 mice, expecting Pelota to take both, but she only took the one and was content. So instead of wasting it, I refroze it. It was only out for no more than an hour, so it wasn't a problem. The next feeding though, since the refroze one was a small weanling mouse, I thawed both the weanling mouse and a fresh f/t adult mouse. She took the weanling as an appetizer, and the fresh adult as a main course. The weanling was noticably different though..a bit more smelly, and the stomach was a bit darker. No ill-effects though. I'd say go for it if you want. It's usually safe to refreeze once...as long as it wasn't out too long.