Hello Mary,
 
I am not a vet, rather a shelter volunteer who works with many recovering
or impaired ferrets.  In my opinion bad ferret breath can be the result of
several things- first I would take the ferret to the vet for a checkup and
blood panel to check for liver / kidney problems.  Bad breath may also be
from an out fo control ulcer or bacterial condition-- only a qualified
veterinarian can help with the diagnosi of this symptom, I urge you to
consult one.
 
Of course it may be something as simple as diet-- you gave no other
indicators-- whether there were abnormal stools, normal appetite, etc.  Are
you perhaps feeding a diet with fish?  this could also cause a noticeable
change in ferret breath.  Hoping your questions are answered soon-- and
your ferret is feeling fine!
 
alicia
[Posted in FML issue 2938]