Iodine to Suppress Ovulation

Additions of iodine to egg production diets have been used experimentally to delay sexual maturity in pullets. A low energy 14% crude protein grower diet with 0, 2,500, 5,000, and 10,000 ppm iodine added in the form of potassium iodide was fed to replicate pens of pullets on litter and replicate groups of pullets in multiple hen cages. All pullets had been grown under nine hours of light per day from eight weeks until the start of the experimental period, at which time day length was increased to twelve hours. The dietary treatments were started at 17, 18, and 19 weeks of age. All pullets were on treatment for four weeks. They were changed to a 16% crude protein layer diet after the four week treatment period.