its happened to me before... scared the living crap out of me... feathers came out and then it was crawling on the floor. Then was the question of where it went.....
mine did that the other day too. I think it just didn't like the spot it was in, so to conserve energy (I read this somewhere), it shed it's feathers. It will regrow them and be back in 1-3 months, apperently. I'm not too worried.
I had a tang that every time my feather duster would grow its feathers back it would pull them off. I did everything I could do but it ended up that the feather duster did not make it.
Sarah
when my feather duster did that, it turned out he was dying. but ive also heard they will move, regrow their calcareous tube and crown. so it could be either......