That's awesome! Very smart.
I just use bungee cords to adjust the size of the opening between my temporary fence and the permanent run. I'm not very clever. I'm just frugal (cheap) and not much of a builder - lol! My bantams fit through that. My big girls can't.
I have one in my run right now! I fenced off an area of my run to keep my hens separate from my chicks but allow both groups to see one another. I left them separated for about a month. I let them free range together occasionally, and things have been pretty calm. So last weekend I made a couple...