POULTRY PRODUCTION AND POULTRY INDUSTRY 45 



Conservation of Soil Fertility. — It is becoming increasingly 

 necessary to market crops in those forms which carry the 

 least amount of the valuable fertilizing constituents away 

 from the farm. It is a matter of common knowledge that 

 live stock and their products offer the best opportunity for 

 accomplishing this. This is owing to the fact that very 

 much of the fertility found in the feed and totally lost if sold 

 in the form in which it is grown, may be returned to the 

 soil in the manure, if fed to stock. 



The approximate values of the fertilizing constituents 

 found in the feed necessary to produce a ton of several of the 

 common food products of animal origin and the value of 

 these same fertilizing constituents found in a ton of the 

 product are shown in Table XII. The products are arranged 

 in order according to the per cent, of the value of the fer- 

 tilizing constituents left on the farm. 



Table XII. — The Pek Cent, of Fertility Left on Farm 

 BY PKODnCTS OF Animal Oeigin.' 



Disease and Intensive Conditions. — ^That the problems of 

 growing poultry are difficult under certain conditions and 

 fairly simple under others is witnessed by the fact that while 

 poultry-farming enterprises of any considerable proportions 

 that have confined their efforts to production and have 

 been profitable through a series of years are very exceptional, 

 the volume of poultry on farms in the United States has 



' Compilsd from various sources, chiefly Sherman, Chemistry of Foo3 

 and Nutrition ; and Henry, Feeds and Feeding. The calculations are on the 

 basis of a per pound value of twenty cents for nitrogen and five cents each 

 for phosphorus and potassium. 



