Oh my, the Moluccan Cockatoo is my favorite. I had one named Boomer. He was the sweetest animal I have ever owned. I wish I still had him. I bought him from a man who was a day trip truck driver, but then went over the road. He couldn't pay enough attention to Boomer. Unfortunately, about 8 months later, he came in off the road. He contacted me and begged me sell Boomer back to him. And I did. Anyway, it could me mites. It could be a lack of iron or iodine. Actually there's a whole list of conditions that could contribute to it. Medical reasons for feather plucking should be examined. However, based on my experience, it is usually something disruptive that has happened inside the home. This could be nearly anything. I am assuming the bird is in single housing. Have you brought a new pet into the home? Has a pet been removed from the home? Has someone in the house started a new job or changed their work shift? Even changing your appearance could contribute to this, such as coloring your hair, or your spouse growing a beard. If there is nearby construction, the noise may be a factor. Have you been lax in your attention? Also the natural behaviour of the larger parrot species is a major underlining factor in determining if a bird is going to pluck its feathers in captivity or not. ie Did it's parents start plucking? Intelligent adult parrots who are content and usually very tame are the ones that will pluck their feathers if they are not stimulated and challenged on a minute to minute basis. The huge aviary concept should be used to stimulate some of these birds by allowing them to interact with other birds as this seems to be the only way to cure a large number of these birds from plucking their feathers. Unfortunately, this is not an option for the individual bird owner.