WOW! I have some of those 4ft and even lower coops. LOL Actually my mini hoop coops. I can move them if I really feel energetic, which I rarely do. I actually intend to raise some of them eventually. OK maybe. Just figured if I get to move with space for my birds, I'll have less to take down and move. But they work fine for the bantams and anything bigger gets yard time, so they work. The sand is pretty easy to clean and since wood is at a minimum I can spray the heck out of them too.I made a lot of cooping mistakes in the first 10 years or so. I still have some coops that are only 4' tall. I did that trying to save money and didn't realize what it is like to crawl into a 4' high space. Everything is at least 7' tall now. The cages within the coops can and are used to raise young, but they can also be used for conditioning birds for show. I raise white leghorn bantams that I show and these small cages are a way to keep them clean. Some have wire bottoms and some have solid wood floors. All have removable perches. They are desingned for short time housing and most are 4' long, but you can't see them in that picture.
This is what I have to keep pristine clean during the winter show season....note all the things that can be dragged through the mud.
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Walt
Now if I had property that I owned, I'd die for your setup. Heck I would anyway, but sure would be nice to be able to do what I want to do.