We got home later than usual the other night (only 10:30) and when I went to shut their door, the coop was completely empty. There was no sign of them.
It was hard to see with my flashlight at the time, but in the morning I found a couple of areas with feathers but nothing else to indicate what might have happened. We are guessing something like a coyote or raccoon got them or scared them off. The next day one guinea came back, limping, but didn't come in that night. I also lost one of the bigger brown birds that night from the other coop.
I'm down to 21 birds now. It seems you have to start with about twice as many chickens as you really want or need because so many get killed.
These photos were taken just a few days before they went missing.