I have two chickens that have episodes where they run around in circles with thier head to the side and the beek is chattering. One of them I know what she got it from. She was attacked by a dog he bit her head and she then had blood coming from her ear. The other one did not show any of these sings before she was 2 or 3 months old. Don't know what happens to her. They are almost a year now. They are the lowest in the pecking order. They love to sit on me or just hang around me when free ranging. They let them selves be bullied around by all the other chickens smaller than them and as big as them.