Some alleles can actually be useful to have in a single copy even if they
are dangerous in double form.  There are among humans some dangerous and
even fatal genetic conditions with certain double helpings of a specific
allele, but those with just a single copy have a benefit such as a
markedly reduced chance of contracting some fatal diseases which are
or have been common to their areas.  I have no idea if there is such a
benefit to the KITT or WS ones and can't recall hearing of such, but
that doesn't mean that there might not at some point be for one for some
variants.
 
 --
Ears which require cleaning once a week or more or smell bad may have
mites or fungal infection so it would be a good idea to see the vet.
 
BTW, behind and little bit down from the ears are glands which have
scent.  Ferrets "face-wash" to distribute that over their faces.  Many
are very private about this but some share the activity with their
humans.  Some of them will hold their noses to make themselves sneeze
hard to help dislodge the scent.  We found this very common in a few who
were prone to having their scent glands plug so we got to used to
dislodging the plugs to help those individuals.  Rubbing or a warm water
on a wash cloth can help when that happens.
 
The ones who like to hold their noses to make themselves sneeze can
very easily be taught to use a handkerchief.  Years ago more people
looked down on ferrets and at times we'd have someone snooty in the
vet's waiting area act that way, so we'd ignore them and pull out a
handkerchief, then with concern we'd ask the ferret, "Want to blow your
nose?" and the ferret would use the handkerchief.  It really shut those
people up fast.
 
 --
No one really has real figures on this, but there are a lot of reports
and things known from other species.
 
My inclination would be to do things like starting the older age twice a
year exams and tests at a younger age, and to read up on what others have
mentioned that they have encountered, like the jaw malformation some have
mentioned and so on.  The archives of ferret-genetics at Yahoogroups and
those of the FML and the FHL (Complete Archives at sonic-weasel.) are
good places to start.
 
It sounds like that ferret may have both alleles leading to pigment
reduction over-all and one of the neural crest disorders such as KITT or
WS which lead to panda heads, so I'd personally be a bit extra vigilant
just to be safest with the individual, I think, in case the combination
may have unforeseen results.
 
 --
I am curious; has anyone kept records on health and longevity based on
size in ferrets?  Certainly, there have been breeders who have introduced
or used breeders who are unusually large.  What numbers do you who breed
them have on health aspects and on longevity?
 
 --
There was a small, private breeder with a marked white line who was
running into marvelous results for the first generation on longevity
and health, but i lost track of who that is.  Are you here?  If so, what
are the health and longevity numbers looking like now?  I know that you
wanted to track 3 generations.  How is it going?
[Posted in FML issue 4065]