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Effects of Sunlight on Laying Hens

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If your hens decrease their egg production, fall is probably in the air. Hens need a certain amount of daylight in order to maintain peak egg laying. Even an hour or two less of daylight changes egg laying patterns. If you want fresh eggs year-round, you can fool Mother Nature by installing lighting in your chicken coop.


In order to consistently lay eggs, hens need about 16 hours of daylight and 8 hours of darkness when they're roosting. Once less than 12 hours of daylight is available, egg productions slows down considerably if not ceases completely. Although you might think colder weather causes the decrease in egg-laying, that's not the case. Even chickens in warm climates produce fewer eggs once the daylight hours decline.

Pineal Gland

The hen's pineal gland, part of her endocrine system, sits above her midbrain, behind the eyes. This gland produces melatonin, which helps regulate sleep and other body functions. As the days lengthen, her pineal gland responds by sending a hormone through her body to her ovary to start producing eggs. As the days shorten, the pineal gland stops sending this hormone. Since the gland is light-sensitive, you can fool it by increasing the amount of light available to the hen during the fall and winter.

Artificial Light

As a general rule, a 40-watt bulb for each 100 square feet of henhouse should suffice to keep hens laying year-round. Use incandescent bulbs rather than florescent lights, as the wavelengths of incandescent bulbs are closer to those of natural sunlight. Put the bulb on a timer so it goes on in the dark hours of the morning rather than at nighttime. Set the timer so that hens have only eight hours of darkness. For example, if the sun sets at 5 p.m., set the timer so that the light goes on at 2 a.m.


Perhaps you're someone who took up chicken-keeping as a way to get back to a more off-the-land lifestyle. For hens, it's natural to lay many eggs in spring and summer and decrease output once autumn arrives. They start up again in spring. Some hens, especially young ones, produce eggs regularly or sporadically throughout the winter. Each hen can produce only so many eggs in her lifetime before she's a "spent hen." The amount varies by breed and individual chicken.