Here's something that's working pretty well in my coop in Ohio. My coop is 32' by 12' with about 6' of one end sectioned off for feed and equipment storage. Standard shed roof about 7' tall in the back(west) and about 10' in the front(east). This coop was built in the 60's of tongue and groove pine, with a tin roof. One window, and one man door, on each short side, and four windows down the front.
When we bought this place about eight years ago the coop had been empty for years, except for the coons, possums, and the ground hogs, who had a good start on a full basement under the cement floor. After patching and coating the roof, splicing in some sideing to repair rot and varmit holes, and paint, I had tight, sound coop. And there lies the problem, it was too tight, built with no vents. I suppose they had used the windows to try to cotrol moisture and condensation, but I could never find the sweet spot, water dripping off the ceiling, respiratory issues with the birds.
I came across the idea in an old poultry book. I installed a (whirlygig) turbine vent in the roof, close to the front wall(high side), about center of the long side, spaced to fall between windows. Below the vent I built a plywood "duct" about 16" square from the ceiling to about a foot above the floor, using the outside wall as one side, and open on the bottom. At the top of this shaft I hinged about a 20" piece of the plywood that would fold flat up against the ceiling, allowing the hottest summer air to draw out the vent. Come winter, close the flap and draw the cooler air off the floor while retaining most of any heat generated by the birds. I installed three modified dryer vents as cool air inlets spaced along the top of the back wall, carefull to avoid placing them above any roosts. This helped alot, but calm nights were a problem. As my coop had electricity, I found some garage sale fans that would fit my purpose. I mounted an older window fan on a slide directly below the vent for the warm flap up weather. I mounted it on a slide for ease of removal for maintenance, about every 30 days I take it out, brush off the feathers, blow it out with the compresser, oil it, (about a 10 minute job). For cold weather I mounted a heavier attic fan near the bottom of the duct, remove the upper fan, close the upper flap, and this keeps a good air mix that has eliminated condensation and respiratory problems.This setup does require power, which has not been much of an issue,(short of Ike last year).
I realize Michigan experiences worse weather(and college football) than Ohio, but this has worked well for me.
big medicine
I do however have an issue I am struggling with and I am hoping I might get some advice. At the roofline I am planning to completely enclose the soffit with hardware cloth then leave the rafters exposed behind the facia. I will be using batt insulation in the 2x4 walls and I am planning one layer of foam insulation from facia to facia front to back with a second layer cut 2" back from the cap plate all the way around. This will leave approximately a 1.5"x2" soffit vent around the entire coop (4'x16'). Do you think this will this be adequate winter ventilation? There will also be some windows I could open but they will be at roost level. The other option would be to leave both layers of foam 2" back from the cap plate which would give me a 3.5"x2" vent opening. Thanks.
