The Influence of Dietary Factors on Egg Shell Quality.

CONSIDERING the amount of work that has been published on the mineral metabolism of laying hens, very little data are available concerning their phosphorus requirements. Literature pertaining to the effect of phosphorus in the diet of the hen on egg shell quality appears to be limited. There is little agreement in the literature regarding the phosphorus requirements of laying hens. Massengale and Piatt (1930) obtained as good production with a level of 0.5 percent phosphorus in the diet as with higher levels. Norris, Heuser, Ringrose, and Wilgus (1934) found 0.5 percent phosphorus to be insufficient for maintaining normal egg production, while 0.75 percent was adequate. Miller and Bearse (1934) obtained higher production on diets containing approximately 0.8 percent phosphorus than on diets containing either more or less of this element. Mitchell and McClure (1937) calculated that a level of 0.32 percent phosphorus should be sufficient for 50 percent production if . . .