I am not familiar with southern California but I would think the weather there would be plenty warm enough to not effect laying, the length of daylight hours could though, the shorter days could have triggered a moult. You could ad a light for a few weeks and see if that kicks their laying back in, I use a low watt compact fluorescent in a daylight spectrum to keep my hens going strong, I plan to shut the light down for a few weeks in early fall to see if they moult and to give them a break, we have always used lights and don't really notice any adverse effects on the birds, they still act like normal chickens. It will also help to feed added protein in cold weather, mine will start to eat their eggs if it drops into the negative temps below zero but in California you shouldn't have to worry about any temperature related issues. Always provide free choice oyster shells as well, I wasn't doing that because people on this forum were always saying if you feed layer you don't need it due to the added calcium is in the feed, well I wasn't getting near enough eggs from my hens and a week after adding the calcium feeder the egg production exploded as well as the birds looked far healthier, their combs reddened up nice and they regrew all their missing feathers and looked just wonderful.
