how would i go about defrosting a xl rat without boiling water?
DO NOT microwave it or boil it. This would cook the rat. Thaw it out in cold water and then place it in hot water for a few minutes to raise the temperature of the rat. Or you can just place it in the fridge the day before you plan on using it.
I defrost my mice in hot water. Just as hot as it will come out of the tap. It cools very quickly so I expect I'm not at all cooking the mice with this method.
Leaving it overnight in the fridge would work, but i prefer to limit the amount of time a food item is defrosted. Once it is no longer frozen bacteria starts to build up, even at refrigeration temperatures.
Under no circumstances should you microwave it. It would both cook the rat, and make a nasty mess in your microwave.
The important part is the rat is defrosted all the way through and slightly warm when you go to feed it.
Microwave it, in a bag with holes in it, also poke some holes in the rat