The hen seemed to be getting along fine with the other four across the hardware cloth, so today I tried putting her and one of the four together in a different pen on neutral ground to see how they got along. They didn't. She attacked the other hen. Not a "get out of my space" attack but a "I'm going to kill you" attack.

Back in her own pen she went.
The EE who kicks is now also being ripped up by her group so I had to remove her to her own pen, too. She has stopped laying.
Now we have a flock of four, a flock of three, another flock of three, a flock of one and another flock of one.

The heat is coming back soon and I cannot manage five different pens in the heat. Just one pen is hard enough. I'll have to come up with some other solution. The only hens who get along well with each other are the flock of four and they don't lay anymore.