I wondered about these questions too. somewhere down the line I saw a reference on here to a book called the behavior biology of chickens (BBC), so I bought it. I read the thing cover to cover, it's fascinating and science based but not too technical.
Lighting is a big part of the book. My take away is that laying hens don't actually benefit much from taking a break from laying in the winter if they are given a proper layer diet. I found with my chickens that the lack of light lead to something akin to depression. before I started adding artificial light, they would go to roost in the dark months at about 3:30 and not come off the roost till 10 AM :~(). Such a level of inactivity was actually leading them to eat so much less that they began to become visibly thin.
In the BBC, they reference studies that showed that because of the way the chickens rest part their brain and trade off, a bit like whales, that they do not benefit from more than 4 hours of sleep a night. To me it's all about finding a good balance. I add a 60W equivalent light to their roosting area that also shines to the floor where their food and water is to extend the day both in the morning and the evening, assuring that they get 12-14 hours of light a day. They are very happy, very healthy and keep on laying right through the winter. They do stop when molting.
Chickens are amazing, they have light receptors in their pineal gland, not all that different from optic tissue, it tracks the light coming through the skull and governs the release of egg laying hormones. Each breed has it's own laying threshold so you need to adjust accordingly. As for whether they will stop laying sooner if you don't give them a break, it is true that they are born with a set number of ovum, but it's not clear that any actually use up all their ovum before menopause, which is governed by a variety of factors.
