I know this is kind of a late response, but it is not a "normal" occurance for feather dusters to drop their feathery heads...they do this when they are stressed (whether it be water quality or a tankmate pestering it). It takes a lot of energy for the worm to grow another head back, and as I have read, they will generally only do this aprox. three times before dying. Definitely move the FD to your 'fuge. It will be very happy there, and feel safe and secure.

W.