Why light matters for laying
Egg laying is triggered by day length. Light reaching a hen's eyes and through her skull stimulates the hormones behind ovulation. As days drop below about 12–13 hours in fall, most hens slow down or stop until spring. Extension recommendations for backyard layers are to keep total light around 14–16 hours. More than 16 hours doesn't help.
Add light in the morning, not the evening
Set the timer to switch on before sunrise and let natural dusk end the day. If the light switches off suddenly after dark, hens are caught off the roost in pitch black. Morning light avoids that problem entirely. Increase light gradually, about 30 minutes a week, rather than jumping from 10 to 15 hours overnight.
Should you light the coop at all?
It's a choice. Many keepers let hens rest in winter, since the break coincides with the molt and some believe it is gentler on older birds. If you do add light, a single warm-white LED bulb of about 5–9 W per 100 sq ft is plenty. Keep it well away from bedding, and use a fixture rated for damp, dusty spaces.
Day length is calculated in your browser using the standard solar-declination approximation (including atmospheric refraction), so results can differ from an almanac by a few minutes.
Gear that helps
- Outdoor-rated plug-in timer (digital with a battery backup)
- Warm-white LED bulb in an enclosed, damp-rated fixture
- Outdoor extension cord rated for the run
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Frequently asked questions
How many hours of light do chickens need to lay eggs?
About 14–16 hours a day for steady laying. Most hens slow down noticeably below 12 hours.
Does a heat lamp count as light?
Red heat lamps aren't recommended for adult coops because of the fire risk. A small LED on a timer gives the light without the danger.
Sources
- University of Arizona Cooperative Extension: Lighting Schedules for Backyard Laying Flocks
- NOAA Global Monitoring Laboratory: Solar calculation details
Last reviewed October 2026. These are planning estimates for hobby flocks. For sick birds, contact a poultry vet or your state extension office.