If you are in NJ then the pet store is placing its license at risk by
not treating.

MANY states currently have laws governing pet stores which require vet
care when needed.

Whichever state you are in contact:
1. Whichever office provides ferret permits because it may have the
   right info on who to contact.
2. The office of your area representative for the same reason.
3. The office which licenses pet stores.

If you don't have that contact info the representative's office data
can usually be gotten from the town hall or local library.

Having documentation, even a photo of the problem, will help. A letter
from a vet on hospital letterhead is best but any documentation helps.

Washing the ferret is going to be insufficient given your description.
The ferret needs vet care and the store needs to have its license
placed at risk.

Another thing you can do is to contact the breeder of the ferrets.
I don't know if the other farms would do this, but years ago when a
pet store about 45 minutes from us was treating Marshall kits badly
Marshall refused to sell to them until they improved their conditions.
(This was years ago.) They did improve the conditions.

They had time to think about it, too, because our vet back then was
able to get letters to the state offices (for which we tracked down
addresses) and that store was banned from selling any mammals for 6
months due to their refusal to treat the coccidia that was found in
multiple mammal species in the store, had to have a vet check all
mammals and treat those who had problems, and then had to transfer
the animals to another of their stores which ALSO had to first have
a thorough check.

They needed a kick in the butt to realize that failure to provide
medical care was going to be a lot more expensive for them than
fulfilling their obligations, and it sounds like the store hold that
ferret you know is similar. For some people that is all that will work.

Sukie (not a vet)

[P.S.]
I just noticed that you are in Canada, but suspect that many of your
provinces will be similar in those regards as many U.S. states.

Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/
http://www.ferrethealth.msu.edu/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
all ferret topics:
http://listserv.ferretmailinglist.org/archives/ferret-search.html
"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)

[Posted in FML 6744]