What I did, and has worked out well is derived from the fact that I am cheap. I prefer frugal, but my kids say I'm cheap.
I built my windows with screen in them, and plexiglass on hinges on the top. These can be opened to allow additional ventilation or closed in winter or really bad weather. I don't have to deal with climbing critters, so my screens are regular window screen. Not a good choice it it within reach of growing bored cockerels. (I have to replace one this spring) Also not a good choice if you have climbing critters, like possums, racoon, etc. If you are in an area with these kinds of animals, I would suggest welded wire or "hardware cloth" for screening. Lots of good ventilation takes what could be a hot-house or an oven, to a nice cool pleasant shady coop in the summers. It can be used in the winter to cut down on moisture buildup inside. Moisture combined with cold is a chicken's enemy. They can handle the cold jsut fine, as long as the air is relatively dry. Add moisture, and you will get frostbite and other respritory issues. These we want to avoid. If you hvae a nice big run for them, my experience is that they will tend to stay outside unless laying, even in the winter. Snowstorms, rainy and windy days they will probably be inside the coop. Some peopl like to open and close the chicken door of the coop morning and night to let them in and out. Some of us leave their door open all the time, unless bitter cold. It is really up to you and how you want to do it.
Chickens can and will get bored occasionally. The smaller the space per bird, the more this happens. When they get bored, bad things can happen. imagine a bunch of girls cooped up together during their time of the month...... Lot of scratch grains, space to move around is important to keeping your flock happy. Happy hens lay more eggs and are healthier. If they are bored, they can start picking/pecking at each other, and can injure each other in the process.
Preparing for chickens can be a lot of fun. Get things ready BEFORE you get your first chicks/chickens. Don't be afraid to ask questions. You WILL get many different opinions. Decide what method of chicken husbandry you want to follow, and go for it.