It is a direct response to lack of improved nutrition in the winter also. If a chicken uses most of it's nutrition trying to survive then they will not lay eggs.Less laying is a direct response to less daylight. Chickens need about 14 hours of daylight which you can supplement with a 40 watt bulb or higher.
I have had gamefowl laying all through the winter with no extra lighting. So with that being said chickens don't really need that 14 hours of light, it helps yes.