My chickens have been producing really well this fall, despite the shortening daylength. About a month ago, I put a desk lamp out in the coop to supply photoperiodic lighting for the hens. Chickens need at least 14 hours of light per day to continue egg production in the winter. Since the photoperiod in my area is currently less than 10 hours, I have used a timer to turn the lamp on from about 4:30 am to 8:30 am.
The last couple days my egg production has been lower than normal. I went into the coop to adjust the time and increase the duration of light from the desk lamp...but found out that the light bulb had burnt out. So that solves it! The hens weren't laying as many eggs as normal because they weren't getting their usual morning supplemental light.
I swapped out the incandescent bulb for a brand new compact fluorescent, so hopefully it won't burn out for a long time.
P.S. It's funny that I'm witnessing such strong photoperiodic responses from my chickens because my graduate research happens to be on the effect of photoperiodic lighting on plants. We are basically testing the effects of different types of light (e.g., incandescent versus fluorescent versus LED) given during the middle of the night on the speed at which plants flower.