I find the best way to defrost rats and mice is to get them out early afternoon, by evening they are defrosted. I then take them and place them on a warm surface (top of dvd player or a warm heat mat) and allow them to warm. Then feed to the snakes. I have been advised not to use a microwave, or hot water and have been told this is one of the best ways.
I took this from the Dolittle Farm website:
Thawing Method for Frozen Rats and Mice
There are many ideas and 'techniques' for thawing Frozen Rats and Mice (FRM). Below is a method DoLittle Farm recommends as best practice to maintain food quality and palatability.
Remove required amount of food from the ziplock pack. Reseal the pack and return to freezer.
Place a single piece of 2-ply, unscented paper hand towel on a heatpad, heatcord or other warm surface (like a VCR that is on). Place the rat or mouse on top of the paper towel. It is a good idea to do this close to your pet reptile's cage, as he will smell the food and become quite excited.
After an appropriate amount of time, turn the rat or mouse over and thaw the other side. Click here for a thawing time chart
Once the rat or mouse is thawed and warm to the touch, check the abdomen for any frozen or cool spots by rolling around between your fingers and thumb.
When satisfied the rat or mouse is thawed and warm (approx 38oC - close to your body temperature), offer to your pet reptile as soon as possible.
A few thoughts:
Once thawed, the longer you wait until you feed, the lower the food quality as gut bacteria has already started digestion again.
Do not use warm water to thaw. It can poach the food (resulting in split skin and guts everywhere) or can wash the scent of the rat or mouse away, leaving it unpalatable.
Do not use the microwave. Cooking of the rat or mouse can occur (if it doesn’t explode first!), or you could burn your pet reptile's esophagus with excessive heat.
I hope this may help,