THE IMPOSITION OF DIURNAL1 OVULATORY AND TEMPERATURE RHYTHMS BY PERIODIC FEEDING OF HENS MAINTAINED UNDER CONTINUOUS LIGHT2

Abstract

IN CONNECTION with experiments on the effect of light on time of ovulation of the first follicle of the hen's clutch, we had occasion to maintain birds under continuous artificial lighting, with ample feed and water available at all times and in quarters from which natural daylight was completely excluded. The hens received fresh feed and water, and the usual maintenance operations were carried out between 8:00 A.M. and 4:00 P.M. The birds were in two completely separated rooms, but were subjected to outside noises and disturbances, such as crowing cocks in the early morning, traffic disturbances, and operation of the elevator over a considerable part of the day. After having been maintained under these conditions for as long as four weeks the hens continued to lay a very large proportion of all eggs during the 12 hour period, 6:00 A.M.-6:00 P.M., and during the last week of continuous and uniform lighting all eggs were laid between 6:00 A.M. and 8:00 P.M.