The majority of adult females will lay duds (infertile eggs) even when not introduced to a male. Some will lay just a single egg while most will lay 2 eggs at a time. If this is the females 1st year laying, then she will not have a set schedule and can lay every 30-90 days apart, or even just lay 1 or 2 eggs the entire first year. Each female is different and until she has been laying for at least 2 seasons, she probably won't have a set laying schedule.