So many things can impact these sort of habits, bathing and excellent nutrition are a great base to work from and you have those under control. Offering shreddable toys, stuffing the cage full of safe chewable branches with leaves, hanging wet Kale carrot Greens ect. in the cage will offer good foods as a toy as well as a healthy choices. The leafy branches gives them plenty of chew exercise and distraction to keep those sharp Grey minds and beaks occupied and in good shape. Suggesting Crape Myrtle, Hackberry, Bamboo and Magnolia as safe to start with, stuff that cage making her work to get from one side of the cage to the other.