Have you ever just tried offering non-stunned animals, not on the forceps to your snakes?
I would imagine a stunned animal that's coming out of the fog would be far more angry and likely to bite than one that's not. Especially one that finds itself on the end of forceps.
I wouldn't know from personal experience, since I don't stun and only feed live. But I also don't have a problem with injuries to my collection. I've been feeding live prey for over three years to my collection, and none of them are scarred.