Try to spray some Bitter Apple (available in most petstores) on the
area's she's prone to biting, the taste should be a deterent to her.
Most ferrets can't stand the stuff.  I also have a biter.  kyba bites
when he is not the fuzzbutt getting the attention.  He rarely draws
blood, but bruises nicely.  Shea was also a biter when we got him only
to find out that he is a deafy and was biting out of fear.
[Posted in FML issue 4999]