Not sure what the scale problem is, rat bite was what first came to mind for me as well.
Feeding live is risky. While snakes are very good at taking down live prey, the feeder animal is not going to offer itself to the snake god for dinner. On the contrary, the rodent will do all it can to get away and will do it MUCH faster than you can react. Rodentsw will bite and have incredibly powerful jaws. Whatever part of a snake they get a hold of, there will be holes and damage. Typically to the body but CAN be the head. I've even heard tell of a snake getting it's tongue bit off - slow death sentence.
Please stop feeding live if you can. Try stunning the rat first and see if your snake will take it twitching. You cna progress from there to full dead fresh killed and even to frozen/thawed/rewarmed prey.
There are some snakes that will refuse all but live. I find even those when hungry enough will eat dead prey and once used to it, will contnue to take dead prey on a regular basis.
-----
Thanks,
Dave Colling

www.rainbows-r-us-reptiles.com
0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)
LOL, to many snakes to list, last count (05/26/2009):
36.51 BRB
29.42 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats 

