ok, well. its at least the way i do it, with good results for snake and mouse.
First take frozen rat and or mouse from freezer. I let sit at room temp for about 15 minutes....if you put straight into a ziploc bag, the toenails poke holes in it sometimes and you end up with rat/mouse soup.
The take rat/mouse put in freezer style ziploc bag, place in a tub of water, so water cant get in bag. Not hot water, just the water from cold side, its alot warmer then frozen!
I change the water 2-3 times, after water gets cold from the rats/mice and in about an hour depending on size of rat, its thawed and at room temp. Always poke your finger on the rat to test make sure its still not cold inside.
I then have one of those heat lamps you see at carryouts etc . I put the rats/mice head under it for about 35 seconds or so, untill it reaches normal rat temp, or just so its warm, helps them hit quicker, and then feed.
Now there are benifits to doing it this way..if you use hot water it can cause the skin to burst when snake coils and you end up with goo everywhere, although i have never seen a snake leave any goo behind, they always clean thier plate.
Also, you dont cook the mouse, which i dont know if it matters, in the wild snakes eat some nasty stuff, but your snakes arent in the wild, you want to keep them healthy...
Also heating the head gives them a target, so you dont get the eating from the middle thing goin on.
I will point out, I have a small clean and healthy collection, so I can take the time to do all of this, if you have hundreds of snakes, im sure this would not be cost or time effeciant.
Good luck
Mike