A Note on Diurnal Variation of Six-Hour Urinary Estrone Excretion by Laying Hens ,

DAILY urinary estrone excretion by the hen is relatively low before laying begins, rises to attain maximal values shortly before or on the day of oviposition of the first egg, falls to somewhat lower levels during subsequent egg production and drops to very low levels immediately on cessation of laying (Common et al., 1965). These earlier results did not include any observations on possible diurnal variations of estrone excretion by the laying hen. Such observations have now been made and the present communication deals with the estrone content of urine samples collected from two laying hens at successive 6-hour intervals instead of 24-hour intervals. MATERIALS AND METHODS Two Rhode Island Red hens were furnished with exteriorized ureteral openings (Dixon and Wilkinson, 1957; Ainsworth, 1964.). Hen No. 1 had been in lay for some months and at time of experiment she was laying a fairly steady 2-egg sequence. Hen No. 2 …