FEEDING AND CAKE OF POULTRY 381 



Mineral matter. — The shells of eggs, which comprise about 11 per ct. 

 of their total weight, consist almost entirely of calcium carbonate 

 (carbonate of lime). Laying hens must therefore have a supply of 

 calcium in addition to that furnished in the grains and other common 

 feeds. Trials by Halpin - at the Wisconsin Station show that calcium 

 is as important as any other part of the ration. Hens produced but 

 few eggs when fed rations excellent for egg production except that 

 they were deficient in calcium. When plenty of calcium was supplied 

 a normal yield of eggs was secured. 



Oyster shells are the best form in which to supply calcium. They 

 should be placed in hoppers or boxes in the poultry house so that the 

 fowls can help themselves. Clam shells, sometimes used in place 

 of oyster shells, are not considered as good. Growing chicks require 

 an abundant supply of both calcium and phosphorus for the building 

 of their skeletons and body tissues. Therefore, unless the feeding 

 stutt's of the ration furnish an abundance of these mineral nutrients, 

 they should be supplied by giving some form of bone. Granulated 

 hone and hone meal are most commonly used. Green cut bone, dis- 

 cussed in the following chapter, furnishes both mineral matter and 

 protein. Trials at the New York (Geneva) ^ and Rhode Island * Sta- 

 tions indicate that ground bone is a better source of these minerals 

 than is rock phosphate. 



Grit, or crushed rock, should also be supplied poultry to aid in the 

 grinding of feed in the gizzard, unless they have access to plenty of 

 coarse sand or fine gravel. Several kinds of rock are crushed for grit, 

 the best form being a light-colored lime rock. Commercial grits are 

 commonly furnished in chick size, medium, and large size. 



Animal food.— Trials at various stations indicate that for the best 

 results poultry should receive animal food of some kind. When given 

 abundant range in summer they secure it in the form of bugs, grubs, 

 and worms. Opportunity for range has a two-fold advantage, for in 

 addition to the free animal food, the poultry destroy insects which 

 would damage crops. Whenever the insect and worm supply runs 

 short, one of the substitutes discussed in the following chapter should 

 always be provided. 



Salt; water.— Salt is needed by poultry as well as by other stock 

 and therefore a small amount should be added to the mash. Wheeler ^ 

 recommends 5 ounces per 100 lbs. of feed for mature stock but ad- 

 vises that young stock be given no salt until 2 months old. 



2 Information to the authors. 



3 Wheeler, N. Y. (Geneva) Bui. 242. 

 4Hartwell and Kirkpatrick, R. I. Bui. 145. 

 5N. Y. (Geneva) Ept. 26. 



