this is a great post! i'll point it out to ini as i think he'll find great interest. we followed one of justin rhode's designs last year, but with pvc to make a mobile chicken tractor (more lightweight with the pvc), but the birds aren't totally happy with it. we may look further into this one! thanks! and congrats on your @ocd!!!
Might wait until I get the next ones written, because things changed at the end.....
We did not use anything very lightweight due to our issues with wind out here (Salatin pen). Also, 75 - 80 birds weigh a lot and it must support them (pasture coop).