Yep, I was thinking it might be a newer integration...but when a bird is removed from a flock can cause a kerfluffle in the pecking order.I had two much older hens when I integrated two years ago. One of them recently died. What are you thinking regarding this--bullying?
I suspected as much, but my neighbors, who are avid birders, just confirmed it. I'm SO glad the hens were only briefly in the run before I decided to cover it, and especially that the chicks did not go in there!