After 24 hours of unusual behavior I decided to take him to the vet, where I was told my rooster was, well, sick. Yes, official diagnosis of sick. Most vets, even large animal vets, do not have much experience with treating chickens. I was told to isolate him from the flock, keep him hydrated and hope for the best. Which is exactly what I did.
I am happy to say that after days of worrying he has made a full recovery.
Hei-Hei paid me for my kindness by attacking me three times in the barn last night...... big thanks I get.