The vet said they could find nothing wrong with her. No signs of disease or infection. She said everything looked normal...except that her digestive system was unusually clean. She said it looked like she had not eaten in a while. I did find what, at first, looked like uneaten food mixed in with their poo. It was probably regurgitated since it looked somewhat digested. I know I saw her eat. I made sure she ate every day. I even brought her downstairs into the kitchen, put her in my lap and hand fed her, so I know she was eating. I should have paid better attention when I was cleaning. Maybe I would have seen if she was regurgitating her food. I've been cleaning their cage 2-3x a day but all their poo looks normal and they are drinking and peeing normally.

Well the good news is the other 4 should be fine. We are not going to rush them to a vet right now but they will ALL be getting a check up within the next week or two. The cats and dog as well. The ferrets and cats are due for their shots anyway.