Welcome to BYC. Pick her up and visually inspect her for lice/mites. Especially check the around her vent area, and at the base of her tail. You can see lice crawling on them. Mites are very slow movers and kinda look like pepper. She also could have ear mites causing imbalance. Treatment would be to put a few drops of vegetable oil in each ear to smother the mites, use an eyedropper to administer the vegetable oil. If she doesnt have lice/mites, it could be a vitamin issue. You can purchase poultry nutri drench at a feed store and give her 3 drops a day by mouth twice a day for about 5 days and see if there's improvement. Hopefully the nutri drench will help. Dont give the nutri drench to her more than 5 days, it can cause diarrhea. Good luck.