PO UL TR r- CRAFT. 109 



CHAPTER VI 



Science in Poultry Feeding. 



148. Where Common Knowledge Fails. Purely practical knowledge 

 and skill, enough for ordinary use, can be acquired without study of the 

 science of feeding. The simple instruction which helps to a common sense 

 understanding of the needs of an animal organism and plain knowledge of 

 the properties of the staple poultry foods, is enough for most poultry keepers 

 enough for all as long as only familiar articles are used in approved combi- 

 nations. But when it is advisable to use other articles or untested combina- 

 tions, this common knowledge fails. It has not equipped the feeder to work 

 out feeding problems for himself. Work at them he may, through a tiresome 

 and expensive course of haphazard experiments, but there is no need that he 

 should follow such a course. An elementary knowledge of the science of 

 feeding, and access to a table giving the analyses of the food stuffs he wishes 

 to use, make it possible for him to formulate rations with absolute certainty 

 as to their theoretic value, and reasonable expectation of their practical feeding 

 value. 



149. Food Requirements of Fowls. The food which a fowl eats has 

 three functions : (i). To develop and maintain its organic structure ; (2). To 

 keep it warm to keep up heat in the body; (3). To furnish the strength 

 energy which is expended in every movement. The chemical elements 

 which maintain these functions are found in combination in every article of 

 food, constituting its digestible matter; in the staple grains they occur in 

 nearly the proportions required by fowls under average normal conditions. 



150. Food Elements may be classed as : Principal and Subordinate. 

 PRINCIPAL FOOD ELEMENTS are : 



(i). Proteids (or protein) albuminous, or nitrogenous matter; in grains, 

 gluten ; in milk, casein ; in meat and blood, fibrin ; in bones, gelatin. Pro- 

 tein is the nourishing matter, supplying material for bone, muscle, blood, 

 feathers, eggs. 



