If the inside coop height is around 20", you can take the roosts up about... 5-6" or so to encourage the chickens to use them. They should NOT be allowed to sleep in the nest boxes, unless you don't mind cleaning them daily and/or picking up poop covered eggs.
BUT - what I would actually do is convert this whole thing into a coop. The footprint is big enough to serve as a coop for 4 birds. So to turn it from 2 small "boxes" (tiny coop above tiny run) into 1 bigger "box" you'll want to remove as much of the inside coop wall as possible, plus the floor. Take out the old roosts too.
Nests might be able to stay as is, or may need to be relocated elsewhere or replaced - depends on the structure of the coop and how things inside stack up once done.
Run a new roost(s) lengthwise across the newly open space. Ideally you’d like 12” per bird but 10” can suffice in many cases.
Board up some of the external wire walls so that the roost area is protected from winds and rain. Do NOT fully cover up all the wire, you need ventilation and natural light, so at the very least a few inches under the roofline should remain open. If your climate allows for it, you can leave entire walls open with just the mesh, but I don't know how cold it gets in winter - though you also make it convertible for the season by covering up open walls for winter, and then uncovering for hot and humid summers.
You will need to add a run. Minimum recommended is 10 sq ft per bird in run (though I'd recommend 15-20 sq ft per bird if you can manage it). Even if birds usually free range, it's still recommended to have sufficient run space for times when they do need to be locked up for any reason.
BUT - what I would actually do is convert this whole thing into a coop. The footprint is big enough to serve as a coop for 4 birds. So to turn it from 2 small "boxes" (tiny coop above tiny run) into 1 bigger "box" you'll want to remove as much of the inside coop wall as possible, plus the floor. Take out the old roosts too.
Nests might be able to stay as is, or may need to be relocated elsewhere or replaced - depends on the structure of the coop and how things inside stack up once done.
Run a new roost(s) lengthwise across the newly open space. Ideally you’d like 12” per bird but 10” can suffice in many cases.
Board up some of the external wire walls so that the roost area is protected from winds and rain. Do NOT fully cover up all the wire, you need ventilation and natural light, so at the very least a few inches under the roofline should remain open. If your climate allows for it, you can leave entire walls open with just the mesh, but I don't know how cold it gets in winter - though you also make it convertible for the season by covering up open walls for winter, and then uncovering for hot and humid summers.
You will need to add a run. Minimum recommended is 10 sq ft per bird in run (though I'd recommend 15-20 sq ft per bird if you can manage it). Even if birds usually free range, it's still recommended to have sufficient run space for times when they do need to be locked up for any reason.
