Here is my coop and run, doves to the right with chicken and dove stuff in other unoccupied aviary
Good call on only putting 4 hens into that coop and run! That's the most amount of birds I would put in that space, and hope they're all friendly to each other.
Very cute setup! Easy to get around in and nicely laid out. See how it goes, you might add some run clutter for them to break up line of sight. Like a flat piece of plywood leaned up against one of the inside walls to make an open ended tunnel, maybe a few tunnels, and/or some tree stumps (moveable visual barrier, and occasional perch). Some upside down plastic lawn chairs to fly thru, around, and on/off of. Things that come up to your knees or lower are tall enough to create more "privacy" for them, which can reduce stress. Also, make sure there's no dead ends, but that birds always have a way to escape (if needed).
A setup that looks cluttered to us can be quite appealing to them. A mix between what they like and what I can clean is usually where I end up. I like the plastic lawn chairs because they're easy to reposition, and you can turn them right ways up and sit in them if you want to.
Juvenile chickens tend to fly a lot and perch up higher, while adult hens, especially heavier breeds, tend to spend most of their time walking around on the floor. They'll use a perch or roost at night, but they're usually more interested in pecking and scratching at the floor of the run, in my experience with the heavy large fowl breeds I've had. The more important chickens get the higher roosts at night.
Here's an idea for you - I give mine food scraps, yard waste (leaves, partially composted wood chips for bugs, occasional grass clippings if they're short enough not to cause crop impaction). Hanging apples, peppers, cabbages, and other fruit and veggies (on chicken skewers) are often great enrichment. Things that people won't eat, but aren't quite bad are prime chicken excitement. The guideline is keep treats 20% or less of daily ration. I look at what they eat over an entire week, and make sure their total treat consumption is 20% or less of their weekly ration. So one week I might give them an apple, the next week half a cabbage, etc.
Have fun with them!!!