This may or may not have anything to do with anything (as I've never personally owned chickens, though we did have two ducks ), but I remember being told when I was younger that chickens go through something in the fall season where they may stop laying eggs for a while. The term molting comes to mind, but I have no idea if that's right or not.

Again, no idea how relevant that is, but I thought I would throw it out there in case (as it is fall).