Figured it out. The big tip-off was blood on the walls of the nesting box. And sure enough, our meanest hen Skittles was sitting in the nesting box, all nice and cozy. She pecked poor Brownie off the nest. Well, I've been meaning to get out to that wintertime neglected coop, I had gotten a bale of hay yesterday to spruce up the nests. So this morning I cleared all the old shavings out of the coop, including the old hay, or what was left of it, from the nesting area. I put new shavings in, some new nesting boxes, one upstairs, one downstairs, put a nice big pile of hay in each as well as hay all along the outside of them in case any hens want to lay next to the boxes, which happens. You never know where they'll prefer to lay. I left enough piles of hay to keep them busy picking out and patting down their favorite spots. When I left the coop, Skittles was settled in the spruced up nest upstairs, and Brownie (who we carried back to the coop) was getting cozy in the nice new nesting area downstairs. And in a little while I'll go back out there and see if Skittles is now in Brownie's area, just to be mean. I'll also keep an eye on Brownie's comb. If Skittles is out to get her, then Skittles is going on a vacation to some other farm. But hopefully the newly organized and newly cleaned and hayed nesting areas will keep everyone happy.
You can't be happy if your hens aren't happy, I always say.