Right now we have four cockatiels in. Three are in perfect feather never tear up their feathers, pluck etc. The last one on the other hand has perfect feathers except for her tail. She will jump around and smash her tail feathers up and then when it starts to look torn she will pluck it all out. Then she grows them back in and starts over again. She never keeps her feathers for longer than a few weeks before they are back out again. We have had her to the vet, blood tests, gram stains etc just to make sure there was nothing wrong with her health to cause this but she is in perfect health, eats well, etc just can't leave those tail feathers along