Fat Requirements of the Hen

Several years ago (Russell, et al., 1941) it was reported by this laboratory that the fat balance of hens on an all-mash ration, consisting of the usual feed ingredients, containing 4 to 5 percent fat, became less positive as egg production increased. In the case of certain individuals it became negative when eggs were laid at the 66 percent production level. This observation led to the question as to whether continued high egg production required more fat in the ration than is supplied by the usual ingredients and whether a lack of adequate amounts of fat in the ration would lead to what might be called a physiological breakdown and thus account for some of the high mortality in poultry flocks. The question also arose as to whether commercial mashes in which the fat content had been decreased to 2.5 percent would, along with scratch grain containing 2.0 percent fat, . . .