Vitamin A and D studies with growing chicks. H. S. Gutteridge, Scientific Agriculture, 13, 1933, p. 374.

In this study at the Central Experimental Farm, Canada, six lots of chicks were fed to determine the efficiency of cod-liver oil and pilchard oil in the production of normal bones and in the prevention of rickets. A basal ration free of vitamin A was fed in five lots, to which the oils were added at either 1 or 2 percent levels. The sixth lot received a standard ration containing 1 percent of cod-liver oil. All lots were irradiated for 10 minutes daily with a mercury vapor lamp except the lot receiving the basal ration only, which received 20 minutes' irradiation.