Backyard chicken coops - how to ventilate without creating draft?

Hi there community,
I'm looking to build a backyard chicken coop to house up to 6 chickens, and I'm having a hard time finding good information about the ventilation needs of backyard coops in Berkeley. I'm aware of the 1 sqft of ventilation/chicken rule of thumb, but I'm planning a coop that will only be about 3' tall inside, with the roost being 20" off the floor -- which means that if I add a 12" tall by 6' wide opening to the top of the wall, that opening will be right next to where the chickens roost for the night -- which all of the sites I've found on the internet indicate is no good, as it will be too drafty for the chickens while they're roosting. I'm a bit flummoxed as to how to provide adequate ventilation without making the coop drafty. I'd be so grateful for any wisdom, advice, or guidance from local chicken keepers!

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Hi There, 

Great question!

I installed 3, 4x10 hardware cloth vents at the top of the Coop and a solar ventilation fan-typically used for marine applications- solar during day with battery for night ventilation. Works great. 


We have four hens in a coop about the height of the one you're planning, with the roost at a similar height. Most of the air flow comes from two screened openings about 8" tall by 30" wide, both at the top of the coop, one facing north and the other south.  When the hens are roosting, their beaks are a couple of inches from the wire. And they are fine.  They are in their fourth summer, still laying lots of eggs, and the only illness I've observed was a case of bumblefoot in the omega bird. When we were planning our coop, I looked at websites that showed chickens wandering around in Wisconsin snow, so I don't think the level of cold we get here is an issue.  I'd be more worried about rain blowing through the openings.

If you want to reduce air flow at the top of the coop, you could provide openings near the bottom.  You may still need some at the top.

Part of the reason for needing good ventilation is that ammonia forms rapidly in chicken manure, is quite toxic, and can injure chickens' delicate lungs.  If you clean out your coop religiously every day and make sure they have good-quality, mold-resistant litter (e.g., pine shavings), you can reduce the ammonia problem.