Okay - this is about all i know on the tattoo issue...
 
Marshall Farms tattoos their ferrets in the RIGHT ear with two dots which
look black and then turn blue as the ferret grows.  Since the ear is pulled
out and away from the ferret to ID it, sometimes the second dot is actually
on the head near the ear or it might be so close to the tip that it mioght
not bee seen.
 
The ONLY ferrets tattooed with one dot by Marshall farms are males that have
been neutered but not descented - usually lab animals.  Marshall Farms does
not release intact females at any time.
 
The MI / Ohio area has some vet and backyard breeders marking their ferrets
in the LEFT ears with two dot tattoos.  this is supposed to mark the ferrets
already neutered and descented, but there have been a few reports of intact
ferrets being marked this way and still have a tattoo.
 
Ferrets from Manitoba, Canada are marked in the right ear with a letter -
looks like it is done by hand and many times it is hard to figure out what
the letter is.  I have seen X, L, T and Z.
 
There are reports of ferrets being marked with double dot tattoos which are
NOT from Marshall Farms - anytime you buy a ferret in a pet shop, you should
ask to see the shipping invoice to see where they came from if it really
matters to you.  Marshall Farms sell direct, with the exception of Denver
Ferrets and maybe a place in FL.
 
Hope this helps.
 
Pam / STAR*
[Posted in FML issue 1425]