Sorry I should have made myself more clear! I place the rat directly from the freezer into a tupperware with a tight lid to stop any bacteria and I make sure that the rat is nice and warm before feeding (I did two warm water changes today over the space of 20 minutes to make sure that the rat was warm then heated the head a little further as I had read that a lot of people go that route)

I may still be heating it too little, I think my worry was in making it too hot and perhaps I'm being overly cautious and need to heat it through a little more! I won't be trying again now until next weekend I was just hoping that if I was doing something wrong myself maybe I could find it out here. She seems very reluctant to come out of her hide to feed and I'm not sure if I should try to entice her out more or just leave her to decide if she wants to come out?