... so I've got to ask: has anyone had success with a very well-ventilated, unheated coop and a large comb/wattle breed in winter temps down to zero F? If success or not, please describe your set-up (Woods––which I think may hold a bit more moisture at times?––top-venting, etc). THANKS.
My Brown Leghorn after a winter with temps down to negative single digits F. Although it didn't stay there long last winter. Lowest sustained-for-several-days-at-a-time temps were around 10F.
Her sister has a comb as large and no damage to her comb or wattles either. The three australorps with smaller combs don't have damage either, of course. I can't have a rooster.
My coop. It is not a classic Woods' as known on this website (it does not have the half monitor roof and does have eave and ridge vents open in the summer); it is Woods' inspired - has proportions based on Woods' plan and the open side.
Summer ventilation is the 5' open side (technically, there is a door but it hasn't been closed in over a year except to paint it.) And two 2x3 windows, eave vents, and ridge vent all of which are open all the time. Two 3' wide doors opposite the windows are open sometimes.
Last winter, I put the two windows in and block the eave openings with pool noodles. I meant to block the ridge vent but didn't get to it before it got cold and then they were doing ok so I left it. I do plan to close that next winter.
I had no frost on the walls or other such signs. It felt dry, still, and comfortable inside all the time. Snow falling off my boots or the little that sifted in through the door evaporated quickly even in the low single digits. When it was warm enough for my hygrometer/thermometer to work, it was warmer and drier inside the coop than it was outside. This was so even though they had an open bucket of water all the time. Well, all the time during the days, it usually froze across by morning even though it started the night warm.
The coop is the back half of the shed. The garden supplies in the front half don't need an open side, lol.
The one picture shows a little snow sifted in sometimes - that was about as much as it ever had, even with a stiff wind from any direction. The vast majority of the time it didn't have any snow inside.
Floor plan shown is to scale. One square = one foot. The roof overhang is inaccurate by a little. I have a flock of five.