Living in California, I (of course) do not have ferrets.  However, the toe
biting may be an early sign of adrenyl lesions.  Check for hair loss and
swollen vulva.  The excessive hormone input can make the sweetest kids
agressive.  I know a ferret named Fancy (Fancy Ferret Fawcett) who started
with toe biting long before the hair loss and other symptoms.  I can also
recommend a vet in the San Francisco area that has lots of ferret
experience, and who performed surgery on Fancy - with a very happy ending.
Dr. Lynn Dustin is very gentle with the little critters, also very caring
and responsive to frantic phone calls.  She called Fancy's mom while on
vacation in Santa Barbara three times one Sunday a.m.  starting at 7:00 a.m.
Nice lady!
[Posted in FML issue 1856]