I have 2 rats and one is fat and the other is skin and bone. When I feed them, the big rat doesn’t let the little one eat, so I feed her separately, but she eats very little and runs on her wheel all the time! She’s all skin and bones. I don’t know what to do! I came home yesterday to find the skinny one cold and delirious-like. I got hand warmers and food, got her better, but I don’t want that to happen again. Please help!