Plucking has different reasons for occurring. The cause does not have to do anything with a care provider treatment or care. My neighbors, a son and mother, have a male eclectus. Much loved, and cared for. He is a chronic plucker and has been for his 15+ years that I have known him. Plucked when rescued from a pet shop, plucked when he lived with me and plucked to this day with his new forever home. Sully loves his care providers and they love him. I see them together all the time. A perfect match.
I have a warm place in my heart for Sully and he for me. After he went to live with my neighbors they brought him over when we played cards. Sully walked from his owner's shoulder to mine. Pecked/kissed me on the cheek with his beak and walked back. Brought tears to my eyes as I believe it was his way of thanking me for finally giving him a warm and loving home where he is safe and much loved. Priceless.