First off, serious venting references are available in pat's info. https://www.backyardchickens.com/forum/viewtopic.php?id=84501 My poor explanation of our setup (movable lid on bolt through wall) got me wondering just how simply venting could be accomplished over an hour with stuff found at home. This is more of an Ornette Coleman sorta job (without the finesse and style). However, this will work fine on the downwind wall of your coop (with a simple overhead cover) and should cost next to nothing (the example is just a template for your imagination to work over). First, place lids (below) on wall where you want to place upper and lower vent, mark/cut/drill your vent hole(s)/ holes for the 5 screws, through the wall (inside of vent hole should be covered with half inch hardware cloth (maybe a PSU fan cover for style - in photo). You will need: one flat head bolt with wing nut and washers/4 screws of appropriate length to your wall depth and 4 nuts/8 washers for those/ either foam or sponge insulation strip/two folgers coffee can lid covers. Excuse the nuts, we're in serious hickory territory at the moment (between the earphones, as well, you bet). First, get the materials together (the spin-to-open coffee cup lid is included to illustrate how vent will function and to maintain the theme). I'm using old folger lids, for this example, as they are translucent: Cut a hole through both lids, at the same location, that approximates the size of your vent opening. Punch holes in centers of both lids for flat head bolt. Punch holes in the lid that will lie flush on the wall for the four screws that will hold it in place (screws in pics for illustration only-way too long) on the wall. the lip of the lid needs to have a bit of insulation, or sealent placed just inside it so as to prevent any leakage in future. Place screws and washers as illustrated/mark&drill holes in coop wall. Glue the bolt head (use a large washer as well) to the inside of the lid (bolt will extend out so the `adjustable' lid can be slipped over it). Sealent or insulation should be placed around the lip of the lid. When screwed to the outside of coop wall, it should look something like this (darkened area on wood represents vent hole). Slide the `adjuster' lid (lip out) over the bolt and attach a wing nut. If you're a style maven, you can screw/glue on a little handle to make fine corrections (leaking capacitor with superglue in my case - see if any chemical reacting excitement might happen...). I'd suggest the current crop of Folgers lids as they are UV resistant and have an infinite number of uses. CAUTION: THIS IS JUST AN EXAMPLE TO RIFF OFF OF (just some chicken jazz). Will work as well on inside wall (might want to have one vent near peak of roof and one very low - pref. below bedding line). It is easier, in small coops, to make the adjustments from outside, rather than futzing around and otherwise bothering the chooks from inside. ed: sp.