Reply to Micki's Post: She has been nick named "Waddles", it's her back legs. They don't seem to go in the same direction as the front legs when trying to walk. She doesn't seem to be in pain but she doesn't jump as high as her half sister [ same sire, different dame], nor can she swat at a feather while standing on her hind legs.
It's like she's missing muscles or tendons.