Your coop needs ventilation. It basically has none once the pop door is closed. You need fresh air coming in and stale air going out and you need a bare minimum of two points to get that accomplished.
You'll need to paint the OSB with something or it is just going to rot as it gets wet and swells. Are the bottom framing and exposed wood pressure treated? If not, the coop and run will start to rot out in a few years. But you can beef this structure up and see how keeping chickens appeals to you then design and build something better before that happens.
The wire fencing you've used to enclose it is not predator proof. You should go over it with 1/2" hardware cloth (on the outside) and install a predator apron all the way around the structure going 2' out. You can use the 2x4 wire fencing material for the apron. Pin down the outside edges with landscape pins and let the grass grow up through the apron.
Secure the cloth to the framing using either hammer in poultry staples or exterior grade screws and fender washers.
Is the sheet of OSB in the run section going to be the human access door? You need to get the door framed out and installed. Use 1/2" hardware cloth to cover the door and make sure you have no entrances anywhere into the run and coop that are larger than 1/2". You have several in the pictures that I can see.
Are you going to install a bump out nest box? You can use
this style.
For ventilation, I would cut about 8" of the sheathing at the top of the front and back walls, add framing as needed, attach 1/2" WC to the openings and reinstall the sheathing top hinged to prevent rain from getting in ( as shown in red below with a matching one in the back. The little blue line represents a prop stick).
I would do the same with a window on the front at roost height. That window can be left open on hot summer nights.
How do you open the coop for cleaning?
Where is the roost inside the coop?
You've got some work to do before the chicks can go outside and the cockerel is not as secure as you may think.
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