WE have one ferret we rescued, who has (had) rickets, so her body is rather squat, short, and "fat" (not really fat, but she has a lot of body to shove into a small set of bones..) anyhow the point is, she often looses hair around her shoulders, armpits, and knees, mostly simply caused by "rubbing" i.e: her arms ( forelegs) rub against her chest a lot and the hair falls out where the "rubbing" happens. This depends on the season and her regular weight gain/loss. She also sheds her coat "suddenly". Some ferrets take weeks to shed, others will shed overnight, and some shed dramatically, to the point where they look bald in patches ... but then it grows back.. usually within a week..(not fully, but you should see new hair growth) I would not be too concerned, unless a/ it doesn't grow back soon, or b/ it starts on the tail ( but that doesn't doesn't sound like your little girl) although it is fall, they do tend to shed coats before bringing in their winter coat, although not as dramatically as they do when they shed their winter coat for a summer one but it does happen. I am guessing that it would depend on the climate you have where you live ? The only other thing could suggest is ? could she be pregnant or having a false pregnancy ? female ferrets will shed coats, especially on their underbelly, when birthing ( or false birthing) is close, they use the hair for nesting apparently..(or are making "access" easier for the kits..) just some thoughts ( sorry, I don't claim to be an expert) Darrin [Posted in FML issue 4656]