It's hard to say when yours will actually start laying. Even in the middle of summer I’ve had some start at 16 weeks, some took several more months before they started. These were from dual purpose breeds like yours. In different years I’ve had pullets start to lay in early December when the days are about as short as they will get but still getting a bit shorter. One of those groups was nine months old when they started, the other was about 5 months old. It wasn’t all the pullets in those groups that started then either, some waited a couple of months longer. I do not supplement the lights to increase day length.
It’s possible yours can start laying this winter, I think you will probably see some eggs sooner rather than later whether you supplement the lights or not. But I’m not going to give you any guarantees.
What you are probably seeing is a juvenile molt, they are the right age. Before chicks reach final size they go through some juvenile molts. They outgrow their feathers and need to replace them. Some people may give you specific ages that they go through this but I find with mine that it can vary some between individuals. What you are describing is absolutely normal, no reason to be concerned at all.
Different things can trigger an adult molt. The main one is the days getting shorter. That one is so strong that practically all adult chickens will go through a molt in the fall/winter when the nights get longer. The hens quit laying and use the nutrition to grow feathers instead of making eggs.
Some chickens are fast molters, some slow molters. Which they are is controlled by genetics. It’s not about how fast feathers grow back, it’s about how fast they fall out. A fast molter can look really bare, you can often see patches of bare skin. With a slow molter you probably can’t tell that she is molting just by looking at her, they fall out that slowly. A fast molter may be over it and back to laying eggs in less than two months, a slow molter may take five months. When the feathers start to fall out they start in the head/neck area and work their way through other parts of the body. With a slow molter the way to tell that she is molting is that you see feathers flying around.
Some, not all but some, chickens will skip the molt their first fall/winter. Pullets will often continue laying once they start all the way until the next fall. Given the age of yours I’d expect them to not go through a full adult molt until next fall.
A lot of people read words like “some” or “often” and consider that an ironclad guarantee that it will happen exactly that way. Real life doesn’t work that way. Each chicken is an individual. We keep them in different conditions. We can tell you what will often happen or what we normally see, but you just don’t get guarantees with individual living animals.
To summarize. You will probably see some eggs this winter, likely in December. You probably won’t see a lot until a little later when the days get longer. It’s always a good idea to regularly check for mites or lice whether you see any symptoms or not, but what you are seeing is almost certainly a juvenile molt, absolutely normal and expected.