One of my chickens stretches its head in the air then bends its neck right backwards until its head touches its back. Between us, we have seen it do this four times, all on the same morning. It is about 3 months old, and looks healthy in other ways. What could this be? My brother had a rooster that used to do this often. He culled it. I don't know if it is significant that his bird was an araucana and mine is unrelated but part araucana.