I've just discovered two patches of barbered feathers on Alice, which has me very concerned and puzzled; they are on the part of each wing closest to her head, and the left side has the most damage. The longest Alice ever stays in her cage is while I'm at work, and when I'm gone during the weekend (which isn't always the whole weekend). She doesn't act any different than she ever has, and acts like a very healthy, happy birdie. She has plenty of toys in her cage, and my cockatiel is in her cage right next to hers in the living room of my apartment. Could it be some sort of separation anxiety? I have never had any of my pet birds do this.