Why Have My Chickens Stopped Laying?

Hens stop laying eggs for a variety of reasons. External or internal stimuli affect hormone levels, which change the condition of the ovary and oviduct, the organs responsible for egg production. The result of these changes is the reduction or cessation of egg production. The most common stimuli that affect egg production are decreasing day length, disease, broodiness, poor nutrition, and stress. However, even under ideal conditions, every hen’s egg production eventually slows down and stops.

Decreasing day length
Days become shorter beginning June 22 and begin to lengthen again on December 22. This change in day length causes hens to molt and cease egg production, a process that may take several months.

Molt
Molting is a natural process that allows the hen to replace old, worn feathers and rejuvenates her oviduct, the organ that “makes” eggs. With the molt, the hen puts the bulk of her energy into feather growth, leaving little for egg production.

Natural molting is a seasonal process related to changes in day length. It usually occurs in the fall after chicks fledge, but in domestic birds it can occur at any time, especially if the hen is exposed to some stress. Rapid feather loss by the entire flock usually is the result of a serious stressful event such as lack of water and/or feed or lighting problems.

Poor nutrition
Diet is very important to maintaining maximum egg production. Chickens require a balanced diet, and any supplementation of scratch, table scraps, garden waste, etc. serves to unbalance the diet.

Stress
Egg production is a hen’s reproductive activity. It is not a requirement for hens to thrive. When a hen experiences stress, even so minimal as to go unnoticed, she may respond by ceasing egg production.

Moving, handling, overheating, fright, and lack of food or water are stresses that can be detrimental to egg production. Protection from the elements and predators, clean and well-maintained facilities, adequate ventilation in closed houses, constant availability of feed and water, etc. will reduce stress and help maintain high egg production.

Age
Eventually, all hens cease egg production. Normally, chickens produce well until they are 2 to 3 years old, and then egg production declines. Molts become more frequent and prolonged, and physical problems with the ovary or oviduct may occur. After all, when a high-producing hen has laid for 3 years, she may have produced more than 30 times her body weight in eggs.

Our Situation
The entire flock is molting. Could be the right time of year for that, but I think our chickens went without adequate water while we were on vacation. We had three ducks sharing the chicken yard. Ducks play in the water all the time, spilling most of it onto the ground. It's been a real challenge to keep the waterer filled. Abi was housesitting while we were away. She hurt her back and moved to Chapel Hill for a few days at the end of our absence so she could have help from a friend. When we got home, the waterer was dry. Don't know how long it had been that way, but that seems to be the point at which the laying pattern changed. Abi had been collecting eggs the previous week. In fact, the morning after we returned home I collected the normal amount of eggs. It was in our first week home that laying ceased.

http://extension.oregonstate.edu/catalog/html/pnw/pnw565/