They'll lay right through the year if they get enough light, my birds kept outside on natural light have been stopped for a couple of months now but I have some getting additional artificial lighting laying great.
I keep commercial strains and if you breed regularly the young stags will breed ok probably from 5-8 months of age, after that they're really getting too heavy unless you restrict their feeding and keep them a bit lighter.
My hens will be around 24 weeks old at Christmas and I often get a few eggs off them just prior to Christmas time when they've been reared with extra lighting, so around 5 months of age
Artificial insemination is not as daunting as it seems though, its fairly easy to pick up and once you're practised its quite a quick job.
Their natural breeding season will be Spring/Summer but my local farm had a (presumed lost) heritage bronze hen wander home with some month old poults on January 2nd this year!!
Mine are kept pretty much 50/50 males and females, as long as the males are reared together I never get much bother although I do fit saddles to the hens to protect them from mating damage with the larger stags.