You do not need four nests, two should be plenty even if you stay with the 12” x 12” nests. I made mine 16” x 16” x16”, mainly because that was my stud spacing and it made framing them in very easy, plus if you cut a 4’ or 8’ piece of wood into 16” lengths you have no waste. I know 12” works for that too but just saying. I personally like the bigger nests for various reasons. 12” will also work. Most building materials come in 4’ or 8’ lengths. If you plan your coop and run dimensions around those you can often build something bigger with less cutting and waste. Your lumber costs may not be any more expensive but hardware cloth or roofing costs may increase. Something to look at. I don’t know how you plan to floor your coop section and I don’t know where you are located so I have no idea of your weather. Heat kills a lot more chickens than cold but depending on where you are you may need to consider both. You need to be able to reach every place inside the coop for many reasons. You need good ventilation, in the winter over their heads works really well but in the summer as much as you can get. Instead of the top part of that coop being 6.5 feet I’d make it 8’. Give yourself enough vertical room to work with. I’m a fan of aprons instead of burying wire straight down. Attach an 18” to 24” piece of wire to the bottom of the run, lay it out horizontal, and bury it maybe 2” which just means taking the turf off and putting it back. The idea is that a digging predator goes up to the fence, hits the wire, and does not know to back up. If your ground is rocky it is much easier to install and very effective. I agree with most of the other comments. Being able to stand up in the run would be a great improvement. One potential problem I see is that chickens poop a lot. The more chickens you shoehorn into a small space the more poop you have to deal with. You may wind up doing a lot of poop maintenance in that run section. It would be nice to do that vertical instead of on your knees. Silkies can’t fly so they require special considerations but for flying birds you don’t absolutely have to have a ramp. They can easily fly up a few feet, though an intermediate step might help. I personally like the side pop door instead of one in the floor but whatever way you do it, it is extremely beneficial to be able to lock them in the coop at times. Say you want to clean the run. How can you do that with the chickens running loose in the run? There will be plenty of other times. Or maybe you want to lock them out of the coop when you are working in there. You might want to look through this. I’m not comparing yours to a prefabricated commercial coop, yours is much better. But by looking at the comments you might see some things to avoid. In my opinion designing a small coop is a lot harder than a larger coop because your tolerances are so much tighter. https://www.backyardchickens.com/t/852529/money-poorly-spent Good luck!