[Hi Tigger!  Welcome back!]
Fur loss:
 
I had 4 ferrets, and one of them lost the fur on his tail, then it
slowly spread up to his body. The others (all in one large cage,
sharing everything) didn't have any symptoms. I had been feeding them
Purina cat chow (and occasionally others). He had been raised on Purina
kitten and cat chow, and had no symptoms until he was around 4-5 years
old. The vet had checked him over thoroughly here -- tests, xray... he
found a slightly enlarged spleen, but was unable to make any other
diagnosis without surgury. We opted out at the time.  When I switched
to Science Diet, his fur grew back. He lived for another year or so
and then died, and we didn't do an autopsy. That was 2 years ago. None
of the others have shown hair loss symptoms either before or after.
 
Diet in general:
My vet recommended a diet of 1/2 - 3/4 Science Diet cat food, with a
mixture of whatever human foods they liked to eat (minus MILK products
- ferrets don't digest them well). I discovered that each had their
own preferences... and I would periodically put out random food for
them, although they ate 99% cat food, I just didn't give them people
food that often. I was amazed at the variety of stuff they'd consume
as a group, and the pickiness of the individuals. One ferret's feast
was another's 'what? you call this food?'
 
Housing
I keep mine caged (I now only have one) I kept the four in a
large outdoor cage 6'x3'.I first had them in my bedroom in NJ (in
cage) and when we moved and gave them a walk in closet with a window
which we kept cracked open (with a screen) they all grew in real
coats, fattened up and seemed generally healthier. I let them out to
play, but I didn't want to 'lose' them and sit or step on them by
mistake (a sometimes fatal one).
 
I have heard the same about ferret training. Since mine spend much of
their time in a cage, I never was successful -- although they tend to
dirty only one corner of their cage (their natural tendency).
 
                Good Luck!
                                *Tigger*
                                                                          
[Posted in FML 0150]