There are also complete diets available in pelleted form. They need a lot of attention and someone to talk to. Safe toys can be offered to help occupy a bird. You can also provide a playpen outside of the cage for activity. Handling birds will help to calm them.
Birds enjoy having their heads scratched.
This imitates the mutual preening activity they do in the wild. Adding a little water to their greens or spraying them lightly with water will also encourage preening. If the bird is mean or aggressive it may benefit from having its wings clipped. This allows the bird to glide downward, but makes it unable to fly. Clipping, combined with frequent handling and patience, will usually settle the animal down.