okay, that's weird

Linnet's tail has gone completely limp. As in it drags on the floor when he walks. It doesn't seem to hurt him, and it doesn't bother him when I touch it or hold it. It's not affecting his ability to walk or anything, so it doesn't seem to be the muscles.

I guess if this keeps up for a few days I should take him in to the vet, but this is most odd. Anyone else ever had this happen? What was it when it did?