A molt could be caused by any of these three: Laying Cycle or Seasonal: Most commonly it is caused by change in daylight hours, which is natural. This can be in fall, winter, or spring. Stress: A sudden decrease in access to feed or water can cause a molt. Sickness: An illness such as something respiratory or vent gleet can cause a molt. That does not mean that molting is unnatural, it just means it can happen for different reasons. Some hens will lay through the molt while others will slow down or stop. It varies based on breed, individual, weather, etc.