Do coops need to be fully enclosed and dark?

[townchicks]

You're right, those small prefab coops don't have much ventilation. That's one of the reasons they are NOT recommended by knowledgable folks here on BYC. Don't judge your coop by those. I can't answer as far as snow and ice, we don't get any here except very rarely, but drafts seem to be more of an issue. I'd be more concerned that with chicken wire on the top, predators could get to the chickens.

 

[True Patriot]

Small and dark is exactly what to avoid. Premade coops are designed with the consumer (you) in mind not the chickens. The more fresh air and natural light in the coop the better. Some go as far as entire walls of hardware cloth. For winter, a roof that will handle any additional ice/snow weight. And the ability to block harsh winds from blowing through the coop. And keeping moisture out. Insulation isn't necessary since they have it built in.
Laying through the winter. The number of hours of light per day is the predominant factor in wether they continue laying. Some provide artificial light for 12-14 hours per day. This keeps egg production higher than without light. The temperature will affect also, but to my knowledge it has to be very low. Most likely not a factor in SC. There are also beliefs that it is better for the chicken to give their systems a rest over the winter and not force egg production.

 

[ChickenCanoe]

I thought I read below a certain temp (40-45*?) that all their energy goes into staying warm and no longer producing eggs. If you can keep them warmer than those temps they lay, if not, no eggs!

While most commercial egg farms keep their layers in climate controlled buildings, for the small flock holder, temperature has almost no effect on egg laying. Extreme heat and extreme cold cause stress. Stress affects ovulation. A couple years ago, I kept a spreadsheet for the entire winter. It tracked daily egg production from 4 flocks of chickens. It also had daily weather: daily high and daily low temps as well as precipitation (snow and rain daily totals).
There can be a cold snap yet when ovulation occurred 24 hours earlier, an egg will still be laid. But if temperature affected production in any significant manner and you draw graphs from the weather and production data, long term you would see a trend. There was zero correlation between temperature and egg production. This included periods well below zero F.
Closed up, dark coops are the worst thing one can have. First of all, lots of fresh air is more important than food and water - as important as those are.
Secondly, light, and more importantly, daily light period in relation to dark period (decreasing vs. increasing) is the most important determinant on production. As light increases vs. dark, hormones encouraging ovulation increase. As days shorten, molt often happens and production usually decreases. So winter is when some find a dearth of eggs. But it isn't the cold. Winter coincidentally is when days are short. If one lives in a warm climate, egg production will still go down when days get short.
I also don't ascribe to the notion that one must keep drafts off of chickens. They descend from jungle fowl that don't live in buildings. They can live in trees. How do you keep a draft out of a tree?
The last coops I built, a complex of 5 breeding units, has huge windows (about 1/3 of the wall) on both east and west walls at roost height. The cold winter wind blows right through the buildings. It has been like that for years and I never get even a sniffle, let alone loss of production or death.

The commentary on cold and drafts applies to "normal" chickens. If one has very fragile and non-cold hardy breeds, that is a different story.

 

[ASD Dad]

I have a mix of birds. Two Cochins, a Wyandotte, Jersey Giant, Austrolorp, a group of Easter Eggers and a mystery bird we are not sure what she is but she lays eggs daily!

My Cochins are so fluffy they look like they would be warm on Everest. The others - not sure how they handle cold.

 

[ChickenCanoe]

Those are all cold hardy breeds.
I've had Jaerhons that don't look particularly cold hardy. Slight, tight feathered birds but, originating in Norway, they are extremely cold hardy. IMHO and experience, I think they are one of the best birds for climates like mine where it can get down close to -20F and close to 120F.

 

[TexasRancher]

We live in Central Texas and have been raising chickens starting this last Spring. The coop was enclosed with chicken wire, top and sides, and also buried under the coop. Hot summer we had a water mister on them and a fan when it was 100+F. Now we are expecting a "blue norther" with 40 mph north winds and wind chill temps around 4F. We mounted steel siding on the north side of the coop and covered half of the roof on the north end for more siding. Figured that would get them out of the awful cold wind and help keep them dry. That's all we can do. I watched a couple of the chicks looking up at the new ceiling and over to the north wall. They seemed skeptical..