The Effect of Varying Levels of Vitamin A in the Hen Ration on the Vitamin A Content of the Egg Yolk, on Hatchability and on Chick Livability

POULTRY producers have long considered it desirable to include large amount of green feed in the ration of breeding hens. Since the discovery and development of our knowledge concerning vitamin A it has been assumed that this green feed was fed to supply large amounts of this vitamin and that vitamin A was closely associated with hatchability and chick livability. Actual corroboration of this assumption by experimental data is limited. Throughout this paper references made to vitamin A refer to vitamin A activity regardless of whether its source is vitamin A, carotene or other vitamin A active substances. Sherwood and Fraps (1934) found that the hatchability increased as the level of heat-dried alfalfa leaf meal increased up to 8 percent of the mash. Later work by these authors (1935) did not show an increase in hatchability for an 8 percent alfalfa group over a 4 percent one. Studies reported by . . .