Ventilation Configuration for a Small Coop

[Sarahs Hens]

Hi there! I am in the process of rehabbing a secondhand coop I purchased and need some advice on the ventilation. The coop is 4’x4’ and is very well build but there isn’t quite enough ventilation. It’s a lean-to style that has vents at the roof totaling a little less than 1.5 sqft. There is a window (which I plan to screen with hardware cloth) that adds another 2sqft. However, I am worried it would be too direct in winter since it will be level with their roost bar. So, I’d like to add more vents… by my calculations about 2.5 sqft of vents. Here is the inside now:

My question is – what is the most efficient configuration? The pop door in the center of the photo faces West which is the average wind direction here (from the West that is). Would I place vents on the East and West walls? And if so, should they both be near the roof, or should one be close to the floor? Here are two examples:

Alternatively, would I instead want vents on the North and South walls?

As for other work, so far I have ripped out the linoleum floor that was inside. I plan to scrub everything down, spray with Vikron S, black jack the floors, and limewash the walls. I also plan to remove the feeder/waterer. The coop has one of those little doors for accessing the nest boxes, but I took those out since they take up so much floor space and will be adding in a plastic next box (lower than the roost.. it’s just in the photo for scale). I will also replace the roost bar, move it higher by about 6 inches (so it’s 2ft off the floor) and closer to the center of the coop. Outside I am finishing up (read "procrastinating on") the roof on an 8x12ft run. Here it is so far:

 

[cavemanrich]

I would install louvered vents on east, and west walls, to prevent blasts of draft during windy winter days. I outlined in blue shape.
I would also install louvered vents on north, and south walls, where I places arrows.
Louvered, because you do not have much overhang to prevent water/snow from entering inside.
I would place your nest box on floor, and install roost bar just above. You can install poop trays under roost if you so think , they would be beneficial to your cleaning efforts.
You do not want the chickens heads to be high, where most of the moving air from ventilation is present.
If your coop/run is totally secure, then you can leave the pop door open during mild weather. (overnight) Closing it in warm weather is an additional layer of secure. You would have to assess the security level of your run.
During winter cold, close up when chickens are sleeping on roost.

WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 

[Sarahs Hens]

Thank you! That is a great solution! Yes I'm planning to have a very secure run. I'd love to leave the pop door open. A thought I had was to cut a hole in the pop door and cover with hardware cloth for summer.. Then I could cover it up in winter.

 

[cavemanrich]

Easier solution is to make another pop door. One screen covered for summer, and other solid wood covered for winter. You present one would be fine as winter version. The summer version would be a sturdy frame with good grade 1/4 inch hardware cloth on both sides for added strength. Changeover would take less than 10 minutes.