Doing better! I put a new feeding station in the coop yesterday, and a log. All very distracting, and this morning hens #2, 3, and 4 were fine. This afternoon I swapped out the red heating lamp for a ceramic reptile one that will provide heat but no light, a new experience for them to be in the pitch dark, and I put another large piece of wood in the coop. More distraction. Then at dusk I reintroduced the alpha hen. Pecking ensued, but not too viciously. Hens #1, 2, and 3 apparently have some business to sort out. Hen #4 knows her place and is staying out of it. They all went to bed without anyone getting hurt. So far, so good.
I am learning from this experience to observe carefully, and to be able to "think chicken", but to stay out of the drama and not interfere unless it's life-threatening. Removing a low-ranked injured chicken and reintroducing her has been an amazingly big deal! It would have been easier for the chicken and me to leave her in the coop in a pet carrier and check in on her often. Next time I'll know.