It would depend on the type of parasite. If you are concerned she may have mites, have her examined by your veterinarian for confirmation. There are over-the-counter sprays that can be used to treat most mites on or off the bird. You can find these products in your local pet store. Read label directions very carefully before using. A warm bath or misting will encourage preening and promotes healthy skin and plumage. Do not use any soap or shampoo. Keep her away from cold drafts when she is wet or damp. Clean and sanitize the cage, bowls, perches and toys. Discard anything that cannot be sanitized. Change cage paper or substrate daily.