What we have discovered is that if I keep vet wrap "anklets" on Katie, she doesn't mutilate at all and she feather plucks less. See the photo of Katie's anklets that (I hope) I have attached. Her favorite color of vet wrap is the hot pink color and she is very good about not taking those off, but If I put any other color on her, she pulls them off pretty quickly. I buy the one inch wide roll of vet wrap, and cut a section that I think will wrap around her ankle twice and then cut the section length-wise down the middle with scissors, winding up with two half inch strips that will go around each ankle approx twice making a really fashionable pink band on each ankle. I mash each anklet band really well all the way around so the vet wrap sticks to itself. It helps if the end of the strip winds up on the back of the bird's ankle and not the front where they can get to it easier.
Dr. Speer was quite fascinated by our discovery. He seems to think that it's sort of like what they have found to be true with people who cut themselves, that if a rubber band is put on their wrist, it stops them from cutting. So he figures that Katie's anklets have a similar kind of effect on her. We don't profess to know why it works, but it seems to, at least it does for Katie and a couple of other birds Dr. Speer has tried it on, How we made our discovery is that I had wrapped Katie's leg in vet wrap because she had made sores on her leg. As the higher sores healed higher up her leg, I kept her lower leg wrapped and just by coincidence discovered that all I had to do was keep a strip around her ankle and she wouldn't pick anywhere on her leg, not even high on her thigh.
I don't know if our anklet idea will work on your bird, but it's easy and certainly worth a try. And if you do try it, just so you know, your bird is likely to pick his foot up and look at it over and over again and may take the anklet off a time or two. Keep putting one back on and mash it on good and your bird should start to get used to it and leave it on for longer periods of time. (Katie leaves her's alone now so well that they fade to a pale pink.)
I might also add that daily mistings, and a soaking wet bath or shower with you at least once a week also helps, but you probably already know that.
Katie says "Anklets rule, rock on!"