I have been obsessing over windows myself, as my coop has not been started yet and my chicks are quickly outgrowing their brooder in my basement! There was a post on here that showed a very unique design that I really liked. The person had double hung windows framed into their coop and then they framed out hardware cloth and attached it to the inside of the coop over the windows using wingnuts or hook and eye fasteners. This made the hardware cloth easy to remove, to get to the windows (to clean them or open/close them.) This could even be done by attaching the frames with hinges on one side, and hook and eye fasteners on the other.
I saved a picture of it.
I saved a picture of it.