https://www.backyardchickens.com/forum/viewtopic.php?id=283812 There is a link to the thread I started about building the Chicken McMansion. I have been working on siding, trim and electrical installation, and today I arrived at building opening windows. I have been noodling on paper over how best to go about doing this, and I had come up with a complex shape I could cut out of a 2x4 that would need a masonite cap, and it was just too complex. What I ended up doing was elegant and pretty simple, and is as wind and weather tight as I know how to build anything. Here is what the window opening looked like before I started, You can see the 2x2 framing, 3/8" CDX plywood on the inside and 1/2" CDX ply on the outside. The whole frame is fastened with Gold Screws. You can also see the lighting fixture inside the coop, with the switch and power receptacle under the rear eave. (The right box cover is on the next Home Depot list). I took a 3/4" cedar fence board, and ripped several 7/8" wide strips off of it, Then, using the table saw (you can certainly use a router too) I cut a 1/2" deep by 1/4" wide slot in the strips... That groove is just deep enough to accept a piece of 1/4" plexiglass. I miter cut the "L" shaped pieces and fit them into the inside of the window frame, supporting the bottom with a 1/8" shim to give the bottom of the window some swing room. Then I laid the pieces out on my workbench, put the plexiglass in the grooves to hold it square, and fastened the corners with 1" wire brads. I removed the plexiglass, and filled the groove with a bead of silicon sealant, just enough to hold the plexiglass in place and seal it to the wood. I then cut 1x3 lumber to fit the frame, and provide an overlap onto the siding. I lined everything up and nailed the spacer to the front piece. The window now fits flush against the siding while the plexiglass and the spacer are inside against the framing. I ripped some 3/4" square cedar and installed a window stop inside against the window, and nailed it into the window frame. You can see how cleanly this installed. The opening beneath the window is the cleanout hatch, and framing the door will be coming up soon. Next I cut a piece of 1/2" hardware cloth, and bent the edges up 90 degrees so that the entire mesh was the right size to fit inside the window frame, and up against the window stop. I used another piece of 3/4" square cedar to anchor the hardware cloth firmly in place. It is nailed for now, but I intend to go back and screw it into place. After that, I will install a piece of metal fly screen on the inside, and screw a couple of pieces of trim wood over the edges to make everything nice and neat. I installed a couple of trim pieces on the outside, along with a couple of hinges, a handle and a pair of locking bolts. I'm not sure I like this the way it is, but it is functional and is as water tight as I know how to build anything. A coat of paint, and it will be set. Here's the front window, sans hardware... I also cleaned out the inside of the coop and vacumed it out. I'm almost done hanging plywood and I hope to finish that over the weekend, weather permitting. The weather is starting to shape up a bit, and if we catch a warm enough day I will try and get some Kilz primer on at least the sides that catch the wind-blown rain. I'm pretty excited about how well these windows turned out. The rule of thumb here at BYC is 1 square foot of ventilation for each chicken in the coop. I have three opening windows that combined give me 7.8 square feet of ventilation, up high where it needs to be, and that much should really help to keep the coop from getting moist and smelly. The plexiglass was about $14 per piece, but it's worth it, and by using the silicon to glue it into the fame, it is structural as well. Conversely, when the weather is bad, I feel confident that no wind or rain is coming in through those window. The hardware cloth makes them relatively secure, and the fly screens will help keep it bugproof. Onward!