I'm trying to convince dh that we need lots of winter ventilation in the coop. He is worried about snow getting in and drafts since we routinely get below freezing temps in the winter and overnight temps are often below zero. The page on ventilation didn't really help ease his concerns (this line: most standard-sized breeds are fine down to freezing and significantly below, as long as the air is dry and relatively still and they have an appropriate-width roost and plenty of food made him comment that it is not "down to freezing" here but below that in the winter, on an almost constant basis. The "and significantly below" part didn't help.) So I pulled out my trusty Chicken Coops for Dummies book and it says this: Any method of venting requires not just a way for stale air to escape, but also a way for fresh air to enter the structure. Normally, your coop's door and/or window will be opened often enough throughout the course of a day to allow this to happen on its own. It does go on to talk about the different types of vents but doesn't give any indication about how many square feet are required or that it's even an issue to worry about. It's really not mentioned a whole lot in the book at all as far as importance. Just very briefly with no guide to how much. Naturally, I have no plans to show him that or he'll think there's no need for any high-up vents... but it's frustrating because now he is going to go ask the same person who told him to start layer feed at 6 weeks of age.