It's good to see that this is just a rumor, however, a lot of Petcos and Petlands do sell ferrets that come from ferret mills. They get their ferrets from Marshall Farms which is one of the biggest suppliers of ferrets in the US. They breed ferrets and beagles and sell them as test animals in laboratories. Check out their add in Lab Animal Magazine:
http://www.guide.labanimal.com/guide...nyd.jsp?b=4350

Another site:
http://www.geocities.com/spsac/marshall_farms.htm

I wish I had done more research before I bought my ferrets, but I won't make that mistake again. To those ferret fanciers out there, rescue your next "weasel" or try to find a reputable breeder.