Unfortunately, plucking starts for no seeming reason. We all, I would think, look inwards at what did we do to cause the behavior. Many times, it is not the bird owner, it is the bird. This is well documented and even the best avian vets in the world admits it is sometimes a mental idiosyncrasy that happens in captivity and cannot be overcome. Even with that data, us loving bird owners will always keep trying to help in any way we can to stop it or at least slow it down until our last dying breath. Yet, no matter what, we still love them just as much regardless and treat them as if their is no imperfection, just as we handicapped children that will remain that way the rest of their lives. You never know, sometimes a breakthrough is made years down the road that helps. The bottom line is hope never fails, we have noting else to hang on to in my opinion. But, yes we all beat ourselves up at times thinking "What if?......".