One of the 10 day old chicks is doing this weird head shake (side to side but it is slow). My daughter called it a tick, like you see in humans that is an subconscious movement. It is not continuous but it does happen several times a day. This chick has a vaulted skull. He/she is eating, pooping, drinking and running around. Everything seems normal other than this head shake thing. I have done a bunch of searches but cannot find anything that really fits what this chick is doing. They are eating medicated chick starter that is fermented and have ACV with mother in their water. No wounds that I can find, is alert and very active. Any ideas?