Lighting

Supplemental Lighting for Laying Hens: 14–16 Hours, Explained

Field guide · Updated October 13, 2026 · about 4 min read

If your hens slow down every autumn, the cause is usually not the cold but the calendar. Egg laying is driven by day length, and many keepers add light in winter to keep eggs coming. Here is how it works and what extension specialists recommend.

How light controls laying

Chickens need light stimulation to reproduce. Penn State Extension explains that photoperiod — the number of hours of light per day — directly affects the production of reproductive hormones, and therefore how many eggs hens lay. The University of Arizona Cooperative Extension describes the pineal gland as the organ that senses changes in light and helps regulate the bird's internal clock and reproductive cycle. Arizona Extension is explicit that the natural winter drop in egg production comes from shorter daylight, not from cold temperatures.

Penn State notes that when day length falls to 12 hours or less — in the U.S. most often in September and October — hens molt and production slows or stops. Without extra light, the University of Florida expects hens to resume laying in spring. Natural molting does not harm hens (Penn State).

How much light?

Source	Recommended total day length
Penn State Extension	16 hours for mature layers; don't exceed it
University of Arizona Extension	14–16 hours; more than 16 adds nothing
Oregon State Extension	Above 12 hours to maintain production; 14–16 typical
University of Florida IFAS	About 14 hours
University of Minnesota Extension	At least 12–14 hours

"Day length" means natural daylight plus added light. In Oregon, for example, day length drops from nearly 16 hours at the start of summer to just over 8 hours at the start of winter (Oregon State), so a winter flock may need many hours of extra light. Arizona Extension stresses never leaving lights on around the clock: hens need a dark period to rest, and excess light causes hormonal and behavioral disruption.

How bright, and what kind of bulb

Brightness: Penn State gives a minimum of ½ foot-candle (5 lux), with bulbs up to 30–40 watts; brighter light can cause stress and pecking. Oregon State and UF use a simple test: bright enough to read a newspaper at bird level. Arizona suggests one 60-watt incandescent or an equivalent 9-watt LED per 200 square feet.
Color: Hens need orange and red wavelengths. Penn State recommends "warm" bulbs rated below 3500K; Arizona also favors warm light.
Type: Incandescent, LED and other bulb types all work if they meet the brightness and color requirements (Penn State). Oregon State says bulb type does not matter.
Not heat lamps. Both Penn State and Arizona advise against them. See heat lamps and fire risk.

Morning or evening?

Arizona Extension recommends adding all supplemental light before sunrise, so hens go to roost naturally at dusk. In the darkest weeks that can mean lights on before 3:30 a.m. If you add light after sunset instead, Arizona advises dimming gradually over 30–45 minutes, because hens see poorly at night and need time to find the roost. Penn State gives the same example: early-morning artificial light with natural sunset.

Use a timer and change slowly

Consistency matters more than anything. Oregon State warns that even a one-day lapse can hurt production and recommends an inexpensive timer. Arizona says forgetting the lights for one or two days can cause a temporary drop or trigger a molt that reduces laying for 6–8 weeks. Change the schedule gradually: Penn State says no more than one hour per week; Arizona suggests 15–30 minute steps every week or two as sunrise shifts.

Pullets

Young birds should not be pushed into lay early. Arizona Extension recommends that pullets follow a naturally declining light schedule from 8 to 20 weeks, because early laying can cause prolapse and limit egg size and lifetime production. It suggests restarting lights at 18 weeks, adding 15–30 minutes per week until reaching 14 hours. West Virginia University Extension describes a similar program: start at 17 weeks with 12 hours of light, then add 30 minutes per week up to 14 hours.

Pros and cons

Pros	Cons
Keeps eggs coming through fall and winter	Electrical wiring in a dusty coop is a fire risk; mount lights out of reach and keep them clean (Penn State)
Arizona Extension says correctly used lighting does not shorten laying lifespan, as hens hatch with far more follicles than they ever lay	Hens get no natural winter break from laying; adequate calcium is essential (Arizona)
Cheap: a bulb and timer	Missed days or abrupt changes can trigger molt or stress-related pecking

Natural light is a valid choice too. Hens on natural light simply take a winter break and return to laying in spring. Oregon State even suggests that turning lights off for about six weeks in a hen's second winter lets her molt more completely before returning to long days. For more on how laying changes with age, see how long hens keep laying, or estimate your flock's output with the egg production calculator.