Very nice construction! Your nest boxes are beautiful. I'm sure my ladies would think the same--in fact with no other sheltered area and given that they are higher than the roosts, my ladies would probably enjoy them so much that they would roost in them at night and in bad weather.
I wish I had your enclosure. If I did I would make a few changes though. I'd definitely lower the nest boxes and slant the top so no one decides to roost up there. I'd also nix the branch roosts and use 2x4s as others have suggested--at least 2 that span the entire width of the enclosure. Not nearly as cool and rustic looking as your branches, but far more functional and healthy for their feet. Also way easier to scrape the inevitable poop from. I would probably at the very least enclose the back 1/3 of the enclosure by the nest boxes so the birds have some protection from wind and rain. I'd put the roosts in that area too, otherwise bad weather is going to drive them into the nest boxes and you'll end up with poopy and broken eggs. Which end I enclosed would be dictated by the direction of your prevailing winds. With the hill behind, I'd imagine that side is pretty well protected already but your birds will need more shelter.
I see that you used hardware cloth on the bottom half--that's great. Don't forget about all the predators that will still be able to climb to get through the chicken wire at the top. Since you have no other enclosed shelter for them, your birds will be VERY vulnerable to predator attack. Raccoons can reach through chicken wire and pull and tear a bird right off the roost and weasels can tear and slip right through, too. If you aren't going to enclose an area, at least consider putting up a shield or some kind of barrier to prevent something from reaching in and tearing at the birds that roost closest to the wire at night. Believe it or not, birds roosting on the ends can been torn through the wire by owls and other raptors.
BTW, I love all your chicken names and it's so cute that you made them each their own sign. With a few simple changes your birds will be enjoying deluxe accommodations.