I've just noticed a few days ago that my flyers tail is missing hair on the top part of her tail. Is this something to be worried about? Her diet is pretty staple and shes not missing hair anywhere else. I've checked her cage to see if she got it caught on anything. Couldn't see any problem areas. Is this just a case of over grooming? I've been told that it could be moult but how long does that usually last? Shes about 4 months old. Any help would be appreciated.