Is my coop a good design and size?
Looks really nice and well ventilated. Plenty of room for 14+ chickens. Better order MORE! Landing bars on the upper boxes, Check. I would only question your local predators and the use of chicken wire. You might want to shout out on your local thread to ask your neighbor what predators they have encountered and how they needed to reinforce their coop/run. Here's a link. http://www.backyardchickens.com/newsearch?search=washington
General rule of thumb is 4sq ft per bird in the coop, 10 sq ft in the run. How big is your coop? Where they roost? They need roost space too to avoid squabbling. Minimum for 14 IMO would be 2 8' roosts at the same height. A lot depends on weather too. 10X30 as a rule is good for 30 chickens, but there are so many variables. Will they be locked up all winter? Look through the threads. There are tons of great conversations to help you decide. Keep the questions coming. One way isn't the only way. I hope you get great input.
Hope this helped!