Should you add a supplemental light in your chicken coop? Will it make the hens lay through the winter? Learn why you might want to add a light bulb to your chicken coop.
Laying Cycles of Hens
Hens naturally lay eggs when the days are long, and slow down as the days grow short in winter. This is because daylight stimulates the pituitary gland, which stimulates the hens' ovaries to produce eggs. Hens lay when they have daylight for at least 12-14 hours per day, and egg production drops off significantly and may even stop once days are shorter than this.
A 40-watt bulb suspended about 7 feet off the floor will provide enough light intensity to substitute for daylight in a small chicken coop of roughly 100 square feet (10 feet by 10 feet or so). For a larger coop of up to 200 square feet, use a 60-watt light bulb.
With a timer to ensure at least 14 hours of light - you can set it to go off when "natural" daylight floods the coop, or keep it on if your coop doesn't get adequate daylight - hens will lay throughout the winter.
When setting your timer, extend the day in the morning rather than the evening, if possible - because if the coop light suddenly shuts off and it's pitch black outside, the hens may become disoriented and not be able to find their roosts in the dark.
Consistency of light is important - so if you choose to act as the timer instead of buying one, you must turn the light on and off at the same time each day.
Should I Use Light At All?
Some chicken keepers believe that giving the hens a rest in the winter is important, and choose to deal with the lack of eggs during the shortest days of the year rather than using supplemental lighting. It's important for you to decide what you're comfortable with. If you have a sustainable, natural approach toward farming, you may decide that respecting the birds' natural laying cycles is important, and you're willing to forgo winter eggs in order to let them live most like they would in nature. If you are producing eggs commercially, this might not be a viable option for your business plan, and supplemental lighting may become part of your chicken management.
You certainly don't have to use light. Personally, I take a hybrid approach. I give the hens a natural rest in the fall as they go through molt and egg production drops and then stops (I live in a northern latitude where the days grow short quickly). Then sometime after the winter solstice, I set up the light and give them long days again. We go a few months without eggs, but not the whole winter.