In these hens, partially or fully formed eggs are found in the abdominal cavity. Such eggs reach the cavity by reverse peristalsis of the oviduct. If they have no shell, they are often misshapen because of partial or complete absorption of the contents. Frequently, only empty shell membranes are present. No control or treatment is known. This condition is related to erratic ovulation and defective egg syndrome. Internal ovulations can happen throughout the life of the hen. Some hens are chronic internal layers.