Years ago, eggs were scarce in the winter months. An egg in January sold for twice what it did in June. Eggs were almost a seasonal food. Supposedly, that’s the story behind egg-less holiday sugar cookies and gingersnaps. Chickens do naturally slow or stop laying in the winter for several reasons. That fact hasn’t changed, but today’s backyard and commercial egg farmers are able to extend egg production through various practices.
In the hen’s reproductive cycle, a yolk is released from the ovary sometime in the morning, the white and shell are formed, the egg is laid, and ovluation reoccurs shortly thereafter. The whole process takes a little longer than 24 hours. It’s more like 25 hours or so in the summer. So, a given hen lays her egg about an hour later each day. It’s clockwork. When she lays in the afternoon, a hen is said to be “running behind”. When she gets to about 3:00PM, the cycle is interrupted because chickens never ovulate that late. The hen rests (resets) and the cycle resumes a morning or two later. In the chicken world, the number of eggs laid in the days between rests is called a “clutch”.
In addition to resting between clutches, a hen goes into a extended rejuvenation phase known as the “moult”. A moulting hen usually stops laying, although some hens known as “slow moulters” continue at a reduced rate. Moulting hens lose most of their feathers and grow new ones. They also use the time to build up spent reserves. It varies with breeds and with the age of the hen, but moulting usually occurs in the fall and lasts around 3 months, sometimes longer. Some commercial producers practice induced molting, where a whole flock is made to molt on a managed schedule. For the rest of us, molting is unmanaged and unavoidable. It’s a major factor in a flock’s seasonal production slowdown. The other big factor is daylight.
Hens need daylight and activity to stimulate ovulation. As daylight decreases, the ovulation cycle slows. It’s nature’s way. Dark and cold winters are not the ideal time to raise chicks. To sustain some laying activity in this period from hens who aren’t already moulting, artificial light is needed. I installed a nifty hard-wired timer switch in our coop. It has a battery to keep time during power outages. It turns on a few hours before dawn and a few hours at dusk, which gives the hens about 16 hours of light per day.
As if moulting and seasonal slowing of the ovulation cycle aren’t enough, egg production is affected when hens go “broody”. Even with daily collections, it’s common to get a clutch of eggs together in a communal nest. If a hen sits on a full clutch for a period of time, she can go broody. A broody hen stops laying. She becomes mother hen, and is fixed on incubating eggs in whatever nest she can find. It can take several weeks, but eventually she figures out the eggs are disappearing each day and that no chicks are hatching. She then returns to ovulation and production in fairly short order. You can break the brood cycle by physically removing her from the nest every time you visit the coop, and collecting eggs more frequently. It takes a while. I’ve had a few very stubborn brooders.
The humble hen is truly governed by cycles and seasons, perhaps more noticeably than the other barnyard animals. All considered, it’s amazing we get any eggs at all this time of year. It just heightens my appreciation for the winter layers.