MANY investigators have demonstrated a direct relationship between the iodine content of the dam's diet and the concentration of this element in the egg (Hercus and Roberts, 1927; Simpson and Strand, 1930; Wilder et al., 1933; Asmundson et al., 1936; Wilgus and co-workers, 1953). The first evidence that hatchability was affected by this relationship was reported by Hollander and Riddle (1943 Hollander and Riddle (1946) who, working with goitrous adult pigeons, noted a delay in hatching by one or more days, frequent deaths at pipping, and failure to completely draw in the umbilicus. Thyroid histology of the weak young showed hypertrophy of the epithelium, hyperemia, and a lack of colloid. The administration of potassium iodide to the adults corrected the goitrous condition and resulted in the production of normal, vigorous offspring.In extensive studies over three generations using practical type rations, Wilgus et al. (1953) indicated that the lowest level of iodine used …