The light needs to be on consistently approx 14 hours per day to have an effect on winter laying.
It has nothing to do with temperature but with the long nights/short days.
Sometimes first year layers will lay all winter without supplemental lighting, sometimes they won't.
Older layers need 14-16 hours of light to lay regularly thru winter. Last winter I used a 40 watt incandescent light(this year I am using a CFL) that comes on early in the morning to provide 14-15 hours of light and they go to roost with the natural sundown. Last year I started the lighting increase a bit late(mid October), the light should be increased slowly, and the pullets didn't start laying until late December. Here's a pretty good article on supplemental lighting. Some folks think that using lighting shortens the years a hen will lay, I don't agree with that theory but I also plan to cull my older hens for soup at about 3 years old.
It has nothing to do with temperature but with the long nights/short days.
Sometimes first year layers will lay all winter without supplemental lighting, sometimes they won't.
Older layers need 14-16 hours of light to lay regularly thru winter. Last winter I used a 40 watt incandescent light(this year I am using a CFL) that comes on early in the morning to provide 14-15 hours of light and they go to roost with the natural sundown. Last year I started the lighting increase a bit late(mid October), the light should be increased slowly, and the pullets didn't start laying until late December. Here's a pretty good article on supplemental lighting. Some folks think that using lighting shortens the years a hen will lay, I don't agree with that theory but I also plan to cull my older hens for soup at about 3 years old.