A rat that is so infested with lice that it has become anemic will be very obvious.
In the wild, snakes eat what they can catch. Do I think it's dangerous to feed off a rat with lice? No, I don't. The snake can handle it.
Do I think it's good practice all the time? No, I don't. For one, all those poor miserable rats. Second, if you can provide a lice free rat, then do it!
I dont agree with the waste of life and food.