224 POULTRY BREEDING AND MANAGEMENT 



eral in the food, concentrates it into egg shells and mixes 

 a little in the contents. All grain foods contain insufficient 

 lime with which to make egg shells and the laying hen must 

 eat grit, oyster shells, or other things, to supply the de- 

 ficiency. "Where high egg production is called for, the 

 mineral matter is a most important part of the food. Its 

 importance should be more fully emphasized. 



The Oregon Station hen that laid 42 pounds of eggs in 

 12 months used in the manufacture of shells practically 

 3y 2 pounds of lime. In addition there was a small quan- 

 tity of mineral matter in the egg contents. The grain foods 

 she ate contained about two pounds of ash. More than 

 half the mineral matter, therefore, was secured from other 

 sources than the grain foods. 



Mineral nutrients are also demanded by the fowl for 

 building up or repairing the bones or skeleton of the body. 

 The flesh and internal organs also contain certain com- 

 pounds of ash. The importance of ash in feeding has been 

 brought out in feeding experiments with hogs. Corn alone, 

 which is low in mineral matter, produced small gain in 

 weight and developed an undersized, fine-boned, over-fat 

 animal ' t characterized by proportionately small kidneys, 

 lungs, heart, liver and muscles, and by a high percentage 

 of fat." A German physiologist proved that animals will 

 live longer with no food at all than with food containing no 

 mineral matter. As to the effect of insufficient calcium 

 (lime) Sherman quotes the following: "Voit kept a pigeon 

 for a year on food poor in calcium without observing any 

 effects attributable to the diet until the bird was killed and 

 dissected, when it appeared that, although the bones con- 

 cerned in locomotion were still sound, there was a marked 

 wasting of lime salts from other bones, such as the skull 

 and sternum, which in places were even perforated. The 

 injurious effects of an insufficient intake of lime is, of 



