In the Northern Hemisphere, we see the circadian clocks at work when the onset of fall in September brings reduced daylight. Our hens suddenly hunker down, slow or stop their egg laying, and seemingly break out in pillow fights every night.
To prepare for winter, their bodies are telling them to drop all the old feathers and regrow new ones for better insulation and weatherproofing.
Since feathers are primarily composed of protein, egg production is often sacrificed in order to channel their protein reserves to their new feathers.
The combination of molting in fall, followed by less daylight in winter, is why your chickens may lay fewer (or no) eggs until spring.
Molting takes a lot out of a chicken, and you’ll sometimes find your flock to be less enthusiastic and energetic during this time. You might think your chickens are sick when in fact, they’re simply in a molt. They might move at a slower pace or retreat from the flock altogether.