Thanks, LG - you're right, it could have been worse. We're thankful it wasn't.
I wasn't sure if he was the only one to go missing. I was so tired when I counted last night, I couldn't figure out if I had 23 or 24 (I don't always count - I also check to see how many of which ones I have in there. "OK, the two white ones are here, four barred rocks - check, three buffs, OK...") But this evening when I went down to check on them, one of my older barred rock hens was outside the run, looking terrible. Lots of feathers missing - I know she was molting, but she didn't look that bad a couple of days ago - and also looks like blood on the back of her neck. It was getting dark, so I just let her in and will check on her tomorrow. She was moving fine, and went straight for the water. If I need to separate her, I can close off part of the coop. So maybe something had ahold of her, and the roo tried to protect her? My guess, anyway. I'll likely never know.