There's a new "nutritional movement" called Slow Food. It's about being healthier by eating what's available, when its available. For instance, sugaring up on fruits like apples, grapes and oranges in the autumn (when they're ready for harvest) to fatten ourselves up for long dark winters; harvesting bitter greens in the early spring to get a jump start on bright long summer days full of activity and less sleep, eating meat and eggs produced within your home town to improve your "biome" or the germs that keep you protected from new diseasy germs, etc.
I wonder if there's any scientific data about this phenomenon? Maybe we're not supposed to eat rich eggs while its cold & dark and we're less active? 
But in answer to your question, we use no artificial light and our 3 year old hens aren't laying anything. The 1 year olds have slowed to 1 egg per 3 days each. They all appear to be healthy with wondrous feathering, hot feet and normal weight, and their poops and vent skin show no sign of parasites, so I have to assume that all is well. They are active and healthy looking birds.