Just a quick update; not much has changed.
Gray is hanging out in the garage. It seemed happy to see me, and almost went back to sleep when I clucked at it and petted it's back. I had to show it where the food and water were - right eye is definitely gooky, although it does open most of the way. The bird is scratching at the eye and shaking it's head. Still only a little beak snot, still rumbly raspy breath.
I just had to add "gooky" and "rumbly" to my spellchecker's dictionary. And now I have to add "spellchecker". How does this computer not speak English?
Anyway, once it figured out where the food was, and got used to walking on newspaper, it ate with enthusiasm, and was still chowing down when I left.
I checked the rest of the flock pretty closely, and held each one close for a few good breaths - no one else has any symptoms at all.
As I expected, the other EE (Elsa) was waiting at the coop door, and kept looking at me as if to say, "WHERE DID YOU TAKE MY ONLY FRIEND IN THE WHOLE WORLD????" Heh.
I still have to read the links that were provided me, but if anyone would like to venture a guess at a diagnosis, I'd be happy to hear it.