it's very important to give them two weeks off laying Rosemary otherwise they will 'burn out' I've been told. Based on my experience 14 hours is excessive. All ours will lay as normal at 12 hours and some will continue down to 9 hours. I think a lot depends on temperature as well, because what they eat is both building eggs and keeping them warm.
Yes a natural dusk is important so they can perch, because their vision in low light is very poor. We tried lighting the coop in the mornings one year with an ordinary 12V bulb with a timer and leisure battery, but the resulting mess inside from spilt feed and water caused by their scramble to feed in cramped conditions led us to conclude that all the extra cleaning up and bedding didn't warrant the few extra eggs.