So my year old female, Bear, is known for being a chunky fat rat. She loves eating and is a very tough thick rat. But after a few days of no out of cage time (dont worry I was making sure they had food, treats, and water) I picked her up to take her out of the cage to play and she is very thin! this was a few minutes ago and I am very worried. Not thinner than my other rats, but its clear shes lost a lot of weight. She's lethargic, slow and when shes on her hind legs to groom she falls over. She can't jump onto higher things. She wont take food from me when she usually grabs it aggressively. I am very worried. What should I do? Any advice? What could this be? I am going to try now to feed her applesauce, bread and yogurt. And give her water. Please help.