I've been at this about a year and continue to strugle yesterday to understand Ventilation, in response to another post yesterday
Ridgerunner wrote:
The difference between a draft and ventilation.
A draft is a breeze hitting them, especially on the roost. Think in terms of wind chill.
Ventilation is an exchange of good air for bad air.
With chickens you potentially have two different kinds of bad air. Wet poop can create ammonia as it decomposes. How much ammonia does poop create? That depends on how thick it is, how wet it is, and the temperature. Frozen poop will not create any ammonia. The warmer it is the more ammonia is created. Chickens respiratory systems are fairly sensitive to ammonia. They will die in lower concentrations that you would.
Ammonia is lighter than air. If there is a hole (ventilation) above their heads, the ammonia will not build up enough to hurt them. It will rise up and go out of the hole.
The other thing that can cause problems is moisture in the air. The higher the humidity in the coop, the more susceptible they are to frostbite. Many people on this forum have reported solving frostbite problems by increasing their ventilation. The moisture comes from their unfrozen poop and them breathing. You’ll never get your humidity below the outside humidity just with ventilation, but your goal should be to match that outside humidity. That’s the best you can do.
Warm air holds more moisture than cold air. Warm air rises. The chickens themselves generate some heat. In unusually cold weather the ground is likely a thermal mass and warmer than the air. If you have an elevated coop this doesn’t help air exchange. You’ll have to rely on the heat from the chickens. A hole (ventilation) above their heads will remove a lot of moisture. Two openings above their heads may cause a lot of air exchange and keep them out of the direct breeze between the two openings.
Each coop is different. We have different prevalent wind directions and different things blocking wind or tunneling the wind to the coop. I can’t tell you exactly what to do in your unique circumstances, but I’m a big believer in having lots of ventilation above their heads in the winter and lots of ventilation below them, level with them, and over their heads in the summer.
