“…The estimates are based upon research work in which carotene, fish liver oils or "unstabilized" vitamin A preparations were used to supply the vitamin. These studies showed extremely variable results and indicated requirements for the young poult, for example, ranging from the neighborhood of 2,400 USP units (Wilgus, 1940;Van Reen et al, 1951) to over 7,500 USP units of vitamin A per pound of diet (Wharton et al, 1949). Very limited published work is available upon which to base a minimum vitamin A requirement for breeding turkeys.…”