Baby with funky leg

Sweet Stewie has not been using her leg for about 3 weeks now and she doesn't squeal or seem hurt when I touch it. She has no bumps under her feet either. Her hip does look odd and is more inward than her left hip. She also tries to scratch herself all the time but can't scratch her back leg, but can do the motion of scratching... just only scratches the ground. She is losing weight, even though she eats a ton. I was wondering if anyone has had this happen? I am really worried about the baby

Kinda looks like a contracted tendon or a tendon that stopped growing. You should take her to the vet and get a proper diagnosis.

please take her to a good vet with the knowledge and experience to treat rats