Why is my bird biting the cage and toy?

after trying to teach her to step up last 2 days and well were trying to let her know us more and when were just talking to her she plays with her toys but when she bites the swing she pushes it and when the other side is nearing her she bites and screams at the toy so is that helping her bite more and when she doesn't play with the swing she bites the cage and many of the bars are already dented so why is she doing that is she hungry we always feed her so why does she do that?