Dietary Phosphorus for Laying Hens

THE phosphorus needs of the laying hen for optimum performance have been the subject of investigation for a number of years. Rather high phosphorus requirements were reported in some of the early literature. A level of 0.8% phosphorus was found by Miller and Bearse (1934) to be required at either 2.23 or 3.0% calcium. Norris et al. (1934) found that 0.5% total dietary phosphorus was inadequate for egg production while 0.75% appeared to be sufficient. Schaible (1941) concluded in a review of mineral needs of laying hens that 0.4% phosphorus was required for egg production and recommended the feeding of 0.5% to allow a margin of safety. The occurrence of phosphorus in the form of phytic acid in vegetable feedstuffs has been one source of trouble in estimating the phosphorus needs of laying hens. It was suggested by Gillis et al. (1953) that the utilization of phytic acid phosphorus by…