Looks good. My chickens prefer to lay eggs up higher. You might want to consider raising the milk crates up. Snakes can get to eggs on the ground too. I live in florida so snakes are an issue. We have rat snakes or pine snakes that go after eggs here. The chickens do feel safer higher up even when roosting. I saw roosting set up once where the owner had poop trays under that came out easily for cleaning. You have a good start and you will adjust it, I am sure, as you go and discover what works best for you. I am just suggesting ideas.
Caroline
Caroline