Charlene,
Some ferrets can and will start slowing down at age 3.  Others may start
later but it is not uncommon at this age.  You say your vet gave her a
clean bill of health - did he/she draw blood for a panel and CBC?
 
I had a ferret slow down at age 2...he's had several panels done (he's 4
now) and a splenectomy, and seems to be doing better now (that happened
when I switched his diet to Totally Ferret).  I think the best thing to
do is cover yourself by getting a panel and CBC done - if those are normal
and your vet doesn't feel any organ enlargement, and the ferret is eating,
acting, urinating/defecating ok, and everything else is normal, it just
might be normal aging.  If you blood work is normal, at the very least you
have established a baseline for future panels - and have given yourself
some peace of mind.
 
Debbie Riccio
WNYFLFA
Rochester, NY
[Posted in FML issue 1215]