That is the thing, the air sac didn't look that way at lock down, the air sac was at the top, as white and bright as this screen when I shined the light in it and now, nothing I heard it peep Friday morning.  And now nothing, no sound of peeping, scratching, rocking, I think maybe the duckling was in trouble but I couldn't help because I had to leave town and came home to this.  At lock down I saw the tooth, it move, alive and well.