My current flock, purchased from a private owner/breeder almost 2 weeks ago, are laying white, pale blue, medium brown and dark brown. The lady that sold them to me has a light in her chicken building to trick the birds into laying during the winter. She also doesn't keep the cleanest coop. Unfortunately, that is normal for many chicken owners. It is also normal for chicken owners to own too many birds, IMHO. Then, they decide it's too much and have a massive sale/butchering, maybe both and give it up.
When Spring comes I will be giving away dozens of eggs/month to my friends, who, in turn, give ME bags of feed. Better than running an egg business and being inspected.
I don't use a light, just a heated dog water bowl. I also have Plenty of ventilation in my always cleaned up coop, although with the high winds yesterday/this week, I closed the two windows and only left the door with the ramp, north side, open.
I will let my birds pack away the calories this winter, put on some more fat and feathers, and accept 1-3 eggs/daily until about March, when I will get more eggs. Chickens have only so many eggs available to lay. I can keep a flock going longer, then butcher 2-3yo's and replace them.
Several of my new birds are only 7 months old, and will grow up bigger.
FORTUNATELY it only took 2 days of throwing them into their coop/shutting them up all night in their coop, for this flock to understand that you go to the coop when it's dusk and stay there until the morning. I THOUGHT it was going to take a whole week to do this.
The coop has plywood pieces to block the wind from the south, west and north. It is on legs and the wind underneath can make it colder.