Biteing Ferret

Question
I have a rescue ferret who is a terrible biter. She doesn't nip, she bites and locks on. We've no idea of her past at all. She no longer goes rigid when we hold her which I know is fear. She is obsessing about food although she is terribly thin. We've just wormed them all so we know it isn't worms. Squeaky toys drive her potty so we tend not to use them anymore, please help us as we are at the end of our tether and our other 6 ferrets are suffering because of her.

Answer
Ferrets often bite for a number of reasons.  The important thing is to be patient and kind.  Make sure you don't put her down when she bites, wait until she stops then put her down.  Do not punish her, not knowing her background means she is biting for a reason and we don't know what it is.  If she is afraid of fingers, then don't make them scary.  Try to move slowly around her, hand feed her treats so she learns hands are fun, and no screaming or sudden moves.  Let her out of the cage and give her time to run around before you try to pick her up.  
Again - hand feed her, allow time to run before picking her up, move slowly and carefully to now frighten her and be patient.  It shouldn't cause the other ferrets to suffer though - don't change your normal schedule or routine, just give her time and a bit of space.