Right now it's most likely the shortened days. Chickens need 12 to 14 hours of daylight to trigger the egg-laying process, I understand. Most of mine went into molt about a month ago, so production dropped off from that, and now we're getting about 8 hours of daylight so we're getting one to no eggs a day.
Yesterday I started adding supplemental light to my coop in the evening to get them back to work. This is earlier than I usually do, but I have some POL pullets I want to stimulate to get with the program. Many people say to add the light in the morning, but I am not, repeat NOT an early riser. Also, you don't need bright light, I believe even a night light will do. I expect it to take a week or so before I see more eggs. Good luck and keep the faith!