We have an old coop in the back yard, that we have repaired as much as we can (it is not ours, this is actually just a rental). A VERY old, open air coop, built after the design popular in the late 1800s up through about the 1950s, which lingered on in a few areas simply because they were THERE.
The front of the coop has chicken wire up over the top half of the front wall. Open to the South. That is important. It catches the sun. The sun falls on the dirt floor and warms it. The floor radiates heat out through the night in the winter. The open front keeps it cooler in the summer than it would be fully enclosed. This coop is a genius design.
Our weather here is pretty cold in the winter. Not Wyoming cold. Not Alaska Cold. Maybe not even Maine or Michigan cold. But pretty darn. Like a slightly gentler version of the high plains in Wyoming. That coop works, even for that.
We have no supplemental light in the coop, no heat. The coop is what it is, and we and our chickens deal with the sagging walls and the holes in the roof that we can't patch. That coop that we were reluctant to bring chickens home to, has taught me some great lessons. This year is proving them once again.
Our chickens have laid at least some eggs every day through the winter so far, and the number of eggs seems to be rising now that the days are getting longer. We still have a couple of hens that look like they stumbled into a chicken plucker in the dark and had a hard time getting away, but the rest have come through their molt and look like real chickens again.
The Wyandottes and the Jersey Giants have laid an average of every other day for each hen. They are young, and did not molt this year. This is one of the factors in keeping eggs going through the winter. We choose NOT to use supplemental lighting that would possibly cause our hens not to molt. We don't want to push them so hard that they are denied a well earned rest to rebuild their feathers - their only protection from weather. So we have to manage our coop differently to assure eggs all winter. Young hens, who come into lay over the summer, generally do not molt, and will keep laying if they are a breed that is able to handle the cold well.
So if I want eggs all through the winter, I need to make sure I have at least half a dozen new hens each year. It appears that two of the feathering out chicks downstairs are pullets, two of them are definitely roos. More eggs in the incubator, so we should meet our need for replacements pretty quickly. We are only using the incubator until we have broodies. We need some hens that are not particularly good layers, because the good broodies are usually not good layers. Older hens, and a few particular breeds, are our broodies.
As the days begin to lengthen out, the hens start coming back. It seems that some will start laying just as soon as the day length increases are noticeable, as the egg production has slowly started to increase since New Year's day. Our motley collection of assorted breeds of chickens all seem to follow this rule, though some need more light than others - even within the same breed.
The hens that don't start laying within a month or so, and do not go broody this spring (they need to do one or the other to earn their keep) will make healthy chicken soup. We will cull about a half a dozen hens over the spring and summer, to keep our flock the same size, and cull based on productivity.
We COULD just replace them all. But I prefer to butcher some of the young pullets (or sell them) rather than cull the older ones that are still laying, so we encourage the broodies. Young hens in their first year just don't usually go broody. This keeps a more stable flock, and gives us the young roos for more tender meat, and some young pullets to butcher for meat also (more tender than the old birds).
We will keep the incubator going, producing chicks every month, to supply our need for either replacement hens, finished pullets to sell, or meat (the roos from the hatchings go to the pot as soon as they are big enough anyway). It also allows us sufficient birds to be selective, and only keep the best ones, so our backyard flock improves over time, rather than just being a collection of whatever we happen to be able to buy.
I'm pleased with that old coop, and given the opportunity to build one, will borrow from the design. We like that it has two rooms in it also, so we can sort chickens when we need to. We would add a feed room onto the end though, if we do build one like it eventually, when we get where we are going.
Most people out here are surprised that we still have eggs coming in, but we kind of expect it. And our hens did not fail us!

Coddiwomple Farm is located the United States.