In the modern era world, it might look something like this:
https://www.homedepot.com/p/TAFCO-W...ge-Awning-Vinyl-Window-White-VA3214/203426845
These are made in various sizes, but this one probably could have been made to fit my 8' x 12' Woods house. The instructions with the window would tell you the size of the opening needed, and these would then just slide in place.
In my parents home (the basement of which is now about 60 years old), the basement windows are found in wells. They look like this, except are galvanized angle iron....but otherwise look pretty much like these do.
The problem with both of these options is the screen. A regular window screen in a dusty chicken house is probably going to clog up and get filthy in no time. So the screening needs to be hardware cloth or my preference, 1/2" x 1" x 16 gauge welded wire.
In his book Woods mentioned that making the windows as being the only thing beyond the ability of someone with very basic carpentry skills. He advised hiring someone to build those for you. I wasn't that bright. After forgetting to check craigslist, then searching through stacks of old wooden casement windows in the salvage shops, habitat for humanity, etc, and coming up empty handed, I got frustrated and built my own. But I have the basic skills and equipment to do it. Simply 2 x 4 lumber ripped down to proper size. Corners fitted with slip joints, etc.
The way this guy does it is the easiest I've seen if you want to try these yourself.
So you may need to make 4 of these. 4?
Two outward opening windows.......but if those are left open, that means big gap that birds or varmints could climb through. So if open, you need a screen on the inside. So for the inside, same framing, but instead of glass, you use the hardware cloth, etc. Both hinge at the top. If windows are down, screens can be hinged up and out of the way. Windows open, screens lowered?
BTW, for my regular windows, I went with cheap (about $20 each) vinyl single pane barn windows from Lowes. No painting. Installed mine so they slide open.
Whatever the case, this is a well vented chicken house. Cheap and loose fitting are actually better than tight.