46 POULTRY PRODUCTION 



Conservation of Soil Fertility. — It is becominii; increasingly 

 necessary to market crops in those forms which carry the 

 least amount of the ^'ahlabIc fertihzing constituents away 

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

 live stock and their products ofl'er the best opportunity for 

 acconi])lishing this. This is owing to the fact that very 

 nnich 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 per cent of the fertility value of the feed required 

 in the production of several common food ])ro<lucts of 

 animals origin rcs]iectiA'ely, including eggs and broilers, 

 which is left on the farm in the form of manure is shown 

 in Table XII. The products are arranged in order according 

 to the per cent of the value of the fertilizing constituents 

 left on the farm. 



Table XII. — The Per Cent of Fertility Left on Farm 

 BY Products op Animal Oeioin.' 



Per cent of fer- 

 tility value left 

 on the farm. 



Buttnr !)f) S.J 



Bacdii , . , . 02 24 



Beef . . 91.94 



Eggs . . . , Sf).,56 



Broilers .S7 20 



Milk ..../., Sd 24 



Cheese . , ... .■>,S . 03 



Disease and Intensive Conditions. — That the problems of 

 growing poultry are difficult under certain conditions and 

 fairly simple under others is shown by the fact that while 

 poultry-farming enterprises of any considerable proi)orti()ns 

 wdiich have confined theirefforts to ]iroduction and ha\-e been 

 profitable through a series of years are rather exceptional, 

 the volume of i)oultry on farms in the United States increased 

 over LS per cent from 1900 to 1910. (See Table I.) 



This means that for some reason poultrymen, who are 

 presumal.ily skilled in the various operations that make up 



1 CoMipili-d fr.jin various sources, cliiefly Sherman, Chemistry of Food 

 and Nutrition; and Henry and Morrison, Feeds and Feeding. 



