My RIR rooster (not sure how old he is but I've had him a little over 2 years) does this head shaking thing. Is it something to be concerned about? He doesn't seem lethargic or anything...acts normal...eating, drinking, mating, etc. Although, a couple of times I have seen him standing with his eyes closed for a brief moment, but then right back to business. He is such a nice roo & wonderful gentleman to the hens, I don't want anything to happen to him. Thanks in advance!