Ventilation vs draft

We have just built a coup this spring and with winter coming, I need to know the difference.We put a ceiling in but it does not cover the whole top. The ceiling is opened all around the edge. 3-4".

I have windows that open on both sides and on the end above the nesting boxes. All the windows open.

carverlin said:

We have just built a coup this spring and with winter coming, I need to know the difference.We put a ceiling in but it does not cover the whole top. It is opened all around the edge.

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Hi and welcome!
It would probably help if you could take and post a picture (or two or three - we never tire of seeing chicken related photos here, lol) of your setup - that way we can see what you are describing vs. answering based off our interpretation of what you describe, which may be totally off base.

I am wondering too, I have a crack in my ceiling for ventilation (and there is a slanted 'tin roof' over that). I just don't get the ventilation thing for winter, because my instincts are to trap the heat in, but I'm leaving it cracked because everyone says to do so.

Toddrick said:

I am wondering too, I have a crack in my ceiling for ventilation (and there is a slanted 'tin roof' over that). I just don't get the ventilation thing for winter, because my instincts are to trap the heat in, but I'm leaving it cracked because everyone says to do so.

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Ventilation is important in the winter because in "trapping heat" you also trap humidity/moisture (chickens' breath, chicken feces, waterers if kept inside the coop are all sources of moisture). Cold, dry air is healthier than warm, most or cold moist air. Warm. moist air breeds illness. Cold, moist air leads to the risk of frostbite on exposed areas of the bird (ie comb, wattle). Chicken waste is extremely high in ammonia - trapping ammonia laden air inside the coop is not healthy for your birds. Our birds are not nearly as delicate and fragile as we sometimes think they are - too often the things that we think they need are exactly the opposite and we end up causing more harm than good.

Keep in mind too, that chickens aren't naked....they have layers of feathers keeping their bodies nice and warm. You don't want to set up an environment for mold, stink, and other nasties. If you have 3" openings all the way around, I think that is a very good thing.
Mine when done will have 3"x18" openings across the entire front (5 of them...1 between each stud), and same across the back. The studs for the roofs are on their ends, so the roof will be approx 3.5" above the double cap and leave me those openings for ventilation.

Wxguru said:

Keep in mind too, that chickens aren't naked....they have layers of feathers keeping their bodies nice and warm. You don't want to set up an environment for mold, stink, and other nasties. If you have 3" openings all the way around, I think that is a very good thing.
Mine when done will have 3"x18" openings across the entire front (5 of them...1 between each stud), and same across the back. The studs for the roofs are on their ends, so the roof will be approx 3.5" above the double cap and leave me those openings for ventilation.

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But it is all relevant, and I guess that is where my particular confusion comes in. I know ventilation is necessary. My coop is only like 3 square feet, and currently there is only a half inch gap along the top edge of the ceiling. If I had even one 3" gap I think it would hold no heat whatsoever. I have big windows on both sides, but I'm keeping those closed for the winter because of wind. Do you think I have enough ventilation?

The Simplest and most Relevant answer to how much ventilation required, is:

one (1) square foot opening all the way in the top part, per chicken !!

Yes, I know, seems big, but chickens do generate a LOT of moisture,
besides the *fumes* generated by their Poop ...

I had a remote reading weather monitor in the coop and by closing off some vents,
I could *see* humidity inside the coop rise to almost 85% !!!
That is too wet for them in the winter months.

Ventilation is removing bad air. Draft is a wind blowing on them. Two different things.

A chicken’s down and feathers trap air in the tiny opening in them. That is great insulation. That’s all they need to well below zero Fahrenheit. Don’t worry about heat escaping the coop. Worry about the heat escaping their feathers. If a breeze ruffles their feathers that lets the warm air out and hurts the insulation. A breeze hitting them hard enough to ruffle the feathers is a draft and bad.

Ammonia is lighter than air. It will rise to the top. If you have an opening over their heads ammonia will escape. It doesn’t have to be a huge opening but you need some. Moisture is a little harder when determining how much opening you need. Warm air rises and holds more moisture than cooler air. The warmth from their breath and evaporating from warm poop will cause warm moist air to rise some but the effect is not great. Still, openings over their heads help more than low down.

If you have openings over their heads that lets the bad stuff out without a breeze directly hitting them on the roost. Ventilation plus no draft.

I live in Tidewater, VA, so our winters are fairly mild, relatively speaking. I have a coop that is open on one side (and it's fairly drafty). Last year, there was a weeks-long cold snap. I covered the open side with a blanket to keep the cold wind off of them. Other than that, they were on their own. Chickens are more cold-hardy than heat-hardy. I would recommend keeping a lot of direct, cold wind from the chickens at night, but otherwise, they should be fine (my coop now has a duckcloth top; the tarp was temporary).

The explanation given by Ridgerunner on the difference between ventilation and draft is good. However one important detail on how to get the needed ventilation is left out.

In order to create adequate ventilation you need two things. A place for the warm moist air to exit and a place for air from the outside to enter and replace it. Simply opening up a space at the top for warm air to leave is not enough.

So you need air to be able to escape from the very highest point, and enter from a lower point to create airflow that will push the moisture out. You just need to make sure that your lower point where air enters is not low enough to blow air across sleeping chickens.

In residential construction of a house with the same roof style as the coop pictured this problem is solved with ridge vent (at the very peak of the roof) for the air to exit and vented soffit (soffit covers the gaps between the top of the walls and the pointed ends of the roof trusses). Gable vents are to be avoided and are only used by contractors who do not understand what they're doing.

So if your roof is not equipped to do this I would need to see more pictures before I could make further suggestions.