Starting in December, I add dry fish-based cat food to her feed because the hens need a lot of protein to form their eggs, and the free range of insects and worms doesn’t give them enough protein. The cold weather sends too many insects to the ground for the chickens to find enough. In spring, summer and autumn there are a lot of insects and you don’t need to give them a lot of store bought feed.
When it gets really cold I also add cracked corn as it has a lot of energy and keeps the chickens warmer. It got up to -7 degrees during the recent arctic blast, and never got above 5 degrees for several days, without additional heat, my chickens never stopped laying, but production dropped about 20%. From about 30 laying hens, I get between 20 and 24 eggs a day.
My family owned a commercial chicken farm for 20 years, chicken houses, so we have a pretty good knowledge of chickens, lol.