I feed only f/t rodents to all my animals.
I start with a container of really warm tap water (the bigger the container the longer the water stays warm) and place the frozen mice or rats in it.
Maybe 10 or 15 minutes later (for mice; longer for rats) I check them. I take the mouse out of the water and hold it in my fist for a while and feel the temperature. It should feel warm throughout. If it's not completely thawed I'll feel the coolness coming through after about 10 seconds or so. If it's cool or cold I'll change the water to new really warm water and put the mouse back in for a bit.
When they're warm all the way through I place the mice in some paper towels and GENTLY squeeze out the excess water so they're relatively dry.
After that, I either feed with tongs or place the mice in a bowl and feed.
With the drying in paper towels they cool quickly, so I feed right afterward while there's still some warmth in them.
I like the really warm water method because it's quick and clean as opposed to leaving the frozen mouse out for hours until it thaws on its own. I don't use extremely hot water because I don't want to cook the mice, and if you use very hot water the mouse also might burst open and make a mess.
Regards,
Bill