I was recently in contact with a mink farmer that had 40,000 minks. He
told me that a fitch is a ferret that is sold for it fur. When selling
the fur from a ferret you mark the form that goes along the fur to the
auction with the word 'fitch'.
 
Usually ferrets that are sold for it's fur are sick ferrets that can not
be sold as pets or labratory animals.  The price of ferret fur is about 1/3
of the price of mink fur.
 
The mink breeder i was in contact with does NOT sell ferret fur.
[Posted in FML issue 1484]