Their first two years are the most productive. As they get older they lay less but they will continue to lay for many years. As far as laying in the winter, it depends on whether or not they molt. Usually in the first year, when they have grown up from chicks, they do not molt and they will lay...
I also live in Central California on the coast but just north of San Francisco in Marin County in a small town called Bolinas here on the edge of the earth. I have 16 hens and one roo. Down to two cats and presently no dogs.