Who knew chickens were so good at telling time?

Over the years all my egg customers have learned that our chickens don’t lay much in the winter.  We all miss the eggs!  Although you might think reduced laying is their response to the cold weather, the primary reason egg laying slows down during the winter is the shorter length of the day.  Chickens apparently lay their very best when there are 15 hours or more of continuous light.  Commercial producers keep their chickens working all year long by keeping the lights on in their chicken coops for large portions of the day and night.  Trust me, even with my small flock, when eggs get scarce it is tempting to turn the lights on.  But my birds live in an unheated, uninsulated coop in Michigan, and it is winter (brrrrr!).  I figure nature has the right idea.  Devoting most of their energy to keeping themselves alive and well in the cold makes sense.  Who am I to tell nature it is wrong?!  So, I leave the lights off and let the chickens decide how many eggs to lay.

Maybe you are thinking “But how do the chickens know how long the days are?”  Well, chickens have a small endocrine gland, called the pineal gland, that uses light to track day and night. It helps maintain circadian rhythms, which control when they are awake, when they sleep and when they lay eggs.  It is located just at the bottom of the brain, not too far from the eyes.  We have one too, and it has much the same role in humans (minus when we lay eggs).   You can hold it responsible for why you get jet lag when you travel long distances into different time zones! And why melatonin, which is produced by the pineal gland, helps reset biologic clocks and reduce jet lag.

But even knowing all of that, each year I am surprised about just how sensitive my hens are to the changing length of the days.  They started to slow down egg production in the late summer and early fall. This year, by the beginning of December, my 30 hens were giving me only 3-4 eggs per day, with most of those coming from 4 pullets (young hens, first-time layers, who often lay through their first winter despite short days). 

According to the internet, immediately after the winter solstice the change in hours of daylight is miniscule and even by early January we are gaining only 1-2 minutes of daylight a day.  That means that as of now, 3 weeks after the winter solstice, we have not yet gained even close to an hour of light.  The change is so gradual that without a clock, I am sure I would not notice any appreciable change in the length of the days.  But not so the chickens! Even in the midst of a few days of bitter cold weather, during which they received no direct sunlight (because I kept them in the coop), as soon as the winter solstice passed, the number of eggs per day started to creep up.  This week egg production appears to be averaging 6-7 eggs per day, almost double what it was three weeks ago.  All this leads me to conclude that despite not having access to clocks, watches, cell phones or computers to help, chickens are amazingly good at telling time!  They certainly are better at it than I am!