Pullets usually lay straight through their first fall and winter. The following year, as 1 yr old hens, they start developing seasonal rhythms to their laying.
They may go broody in the spring, which will stop their laying. This is when they try to set on a clutch of eggs, to hatch chicks. Most of my hens haven't been particularly broody, but I have several now that were especially bad their first spring. They all went broody that year, some 2 or 3 times! They're almost 4 years old now. Fortunately, they were better starting with their second spring as adults. Last year I think only 2 went broody. They were still laying an egg almost every single day last year. So, I can't complain.
They normally do a heavy molt in the fall as adults, which may stop them from laying. Some chickens still lay when molting. Your entire flock may not molt at exactly the same time or in the same way. Some chickens molt very slowly. Some chickens drop a lot of feathers all at once and need to regrow them all at once. That calls for a lot of protein, especially methionine, which is already in short supply in plant foods. If their body doesn't have enough extra protein to create both an egg and feathers, it will choose feathers. You can supplement their diet with more protein to help them.
Chickens are sensitive to the length of the day. When the days grow shorter as winter approaches, many adult chickens stop laying. Some breeds are better winter layers than others. You can give them supplemental lighting to keep the days at a standard length for them or let them take a rest for the winter. People do it both ways.
What you can run into is a situation where the chickens stop laying because of a molt and then don't start up again until spring, because the winter days are too short.
What I do is add supplemental light, so they have a consistent day length, starting in the fall and going until spring. Before they start molting in the fall, I set aside a few more eggs in the refrigerator. Clean eggs, that still have the bloom on, have been known to last 6 months in the refrigerator. I don't keep them that long, but I do have some set aside so I have enough for a supply during the fall molt. Since I have lighting, my chickens go back to laying after the molt, so I have winter eggs. If you end up with a lot of broody hens in your flock, you can also set aside a few eggs for the spring broody season, too. If you decide not to use lighting in the winter, you can set aside more eggs to get you through more of the winter.
