I so appreciate all this info. This seemed to start when I started to allow him out of his cage more. My husband lost his job, so I suggested, with him home more he could allow the birds out more. The rule had always been people home cages open. But as we allowed more freedom,the plucking began.
Our vet then suggested smaller cage and keep it covered on the top to allow him to stay calmer. But this just made him more afraid of strange noises or people in our home, so on the suggestion of another grey owner I moved him to a large cage, covered on one top corner, and he seems happier now... and as I said we now have tail feathers... I just want to do everything I can for him