How old is she? And have you weighed her? If she has joeys IP, you probably want to see if there is a modification to the diet you're currently feeding for breeding gliders. Is she a picky or healthy eater? Just based on the fact that her coat is softer/fuller/thicker is a testament to better health, anyway. She may in truth be a tiny lady. Find out where she's at before deciding if she needs to gain. :)