Im not sure where you are located, but down here in FL there are little tiny gnats that annoy the heck out of the chicks. At first I thought there was something wrong with them, but as I looked more closely I noticed the gnats. Darn Florida and its bugs!!! Last year I had them too, but they seemed to run their course and then they were gone. My chicks from last year have grown up just fine and are laying like crazy, and no more head shaking.