This is the circle of natural life.
I fed only live and don't have a problem with it.
Yes once in a blue moon someone will get a nip or scratch but that is up to us to keep an eye on them.
F/T is more of a pain in the hind end to me and I don't see a benefit to it.
I do know for a fact that they don't get a rat that was heated with a blow dryer in the wild, much less getting one every week.
True, I just worry that that "once in a blue moon" could involve an eye (Could happen with OP's case of not being able to see either head). They don't get clean, climate controlled cages in the wild either