I have adopted many ferrets that were considered biters.  The usual first
step is to allow myself to be bitten without retribution so that I can
learn under what circumstances the animal bites.  I have had biters that
were deaf, physically sick (adrenal disease), frightened, weaned too early,
or just aggressive.  My experience is that I have had to tailor the
re-training to the specific individual based on my understanding of what
triggers the behavior.
 
My choice in foods is a roughly equal mixture of Iams Kitten, Nutro Kitten,
8 in 1 Ferret Food, Eukanuba Kitten Chicken & Rice, and (new addition)
Totally Ferret.  These work for me & except for the TF are usually fairly
easy to find locally.  I use a blend because the idea of trying to switch a
ferret from one (discontinued) food to another brand is too scary to even
contemplate.
 
The (many) litter boxes scattered around the corners each sit on an old
pillow case.  This is handy for butt wiping, fuzzy plops just outside the
box and reminding me (cause I use a certain color rotation) just where I
stopped in the clean box & litter symphony that is my life.  <VBG>
[Posted in FML issue 2468]