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ALTHOUGH many phases of the calcium metabolism of the chicken have been studied, very little attention has been given to the effect of the calcium and phosphorus content of the diet of laying pullets and hens on the production and hatchability of eggs. The purpose of this paper is to present data on this phase of the calcium and phosphorus metabolism of the chicken. These data demonstrate the deleterious effect, hitherto unsuspected, of a high level of calcium intake of laying chickens on the ability of their eggs to hatch, and they suggest that in practical poultry husbandry it is very desirable to control the calcium intake of laying chickens. LITERATURE Wheeler (1919) made many inorganic analyses of the shells of eggs and of the carcasses of chickens and ducks that had received calcium, magnesium, and strontium from several sources as supplements to their diet. He found that the diets . . .

INTRODUCTION SOYBEAN meal is widely used as a protein concentrate in the diet of laying fowls. Its value for egg production is not disputed. Hatchability of eggs produced by birds receiving diets containing soybean meal, at least that made from some varieties of soybeans, probably depends on the kinds and amounts of animal protein concentrates included in the same diet. Direct sunlight is a very important factor in the production of hatchable eggs. Byerly, Titus, and Ellis (1933) showed that meal made from the Mammoth Yellow variety of soybeans was inadequate for the production of eggs of high hatchability by semi-confined birds that received an all plant-source diet containing about 20 parts per 100 of the soybean meal. Subsequent studies have shown the Illini variety of soybean to be deficient in the same manner. Nestler, Byerly, Titus, and Ellis (1936) showed that the deficient factor in the diet used was . . .

BYERLY, Titus, and Ellis (1933) found that diets consisting of cereal grains, their by-products, alfalfa leaf meal, minerals, and cod liver oil are deficient in some factor, or factors, necessary for the production of eggs of high hatchability. This deficiency is satisfied by range, milk, and certain protein concentrates of animal origin, but not by certain protein concentrates of vegetable origin. Recent investigations by Halpin, Holmes, and Hart (1933) indicate that many diets for laying hens are deficient in vitamin G, and that the hatchability on such diets is low. Their basal diet, composed of yellow corn, oats, wheat bran, wheat middlings, meat scraps, common salt, and cod liver oil, plus scratch feed, grit, and crushed oyster shell, gave a hatchability of only 11 percent whereas the addition of skimmilk or chopped alfalfa hay to the diet raised the hatchability to over 70 percent. In order to determine if vitamin . . .

Occasionally because of unusual circumstances, plant seeds not ordinarily produced for animal feeding become available for that purpose. This paper reports two feeding trials, one with chicks and one with rats, in which Chewings fescue seed of very low germination was fed. Because of the similarity in chemical composition of the fescue seed and oats, a comparison was made between diets containing these materials. The control lot of 25 chicks received a practical wartime chick diet having the following percentage composition: ground yellow corn 30, ground wheat 20, pulverized oats 10, alfalfa leaf meal 8, soybean oil meal 25, sardine fish meal 2, dried skimmilk 2, riboflavin supplement (250 micrograms riboflavin per gram) 0.475, limestone 1, bonemeal 1, manganized salt .5 and activated animal sterol (2,000 units vitamin D per gram) .025. One lot of 30 chicks received a diet containing 30 percent of oats in which oats replaced a . . .