PROGRESSIVE POULTRY CULTURE 31 



to take bodily exercise. By making them scratch for 

 at least a part of their living, the circulation of the 

 blood is increased, digestion is improved, there is flesh 

 formation in place of fat deposition and' active opera- 

 tion of all the bodily functions. The fowls are lively, 

 sprightly and healthy. Their eggs .prove to be fertile 

 and yield chicks which are vigorous, thrifty growers. 



CO-OPEBATION OF INFLUENCES. 



The influences of the three great groups do not 

 act separately and independently in the development, 

 growth and' breeding of the fowls. Rather are they 

 commingled and combined in their action so that it is 

 very difficult and oftimes impossible to determine just 

 what influences have produced certain results in the 

 animal organism. 



Evidently there are some influences that the poul- 

 tryman cannot control and others which are only par- 

 tially under his command, but there remain many con- 

 ditions which are entirely within his power to regu- 

 late. His part in the breeding of the beautiful and 

 useful birds is to exercise his power of selection as 

 applied first to the parent birds which are the medium 

 of hereditary influences, second to the surrounding con- 

 ditions of the breeding stock and the progeny and third 

 to the management of the fowls in the use of their func- 

 tions and productive powers. 



Considering what a multitude of agencies are co- 

 operating in the breeding and growing of a chicken, 

 the poultry breeder is compelled to acknowledge that 

 he can never know these factors too well if he is to 

 learn to manage them successfully for producing per- 

 fect poultry. 



Many men have given earnest thought and careful 

 study to the problems of stock-breeding. Some of the 

 facts developed in the experience of breeders of domestic 

 animals in the past, are stated in the following brief 

 explanations of what are sometimes termed 



