Welcome to BYC Snowgirl. All of the answers you have received were really on point. I'm a bit curious the one that isn't laying does she stay on her nest all the time or recently expressing any behavioral changes. I realize it is late in the season but was thinking if she had been a layer and stopped it is either A) changes in seasonal sunlight or B) Your hen may have gone "Broody" and wants to sit on a nest and raise chicks(less likely do to the late season). or C) Something else. Best of luck in your search for the correct answer!