46 Report or tHE Department or AnrmaL Huspanpry OF THE 
INTRODUCTION. 
One of the most important questions to consider in the feeding 
of poultry is the relative efficiency of the protein or nitrogenous 
matter in different foods and the economy of their use. While the 
several principal constituents of foods may all be sources of 
energy and of material for the large amount of fat stored in the 
egg and in the body, nothing except the protein, or several nitro- 
genous constituents, can supply the necessary nitrogen. Inas- 
much as the more common and cheaper foods all contain heat and 
fat producing constituents in abundance, the source of the nitro- 
gen naturally receives first consideration. 
As a rule some forms of protein can be obtained at much less 
cost in grain foods and various by-products derived from grains 
and seeds than other forms of protein from animal foods. It is 
therefore of immediate practical importance to know whether the 
cheaper rations, consisting entirely or largely of vegetable foods, 
are efficient enough to be economical, or whether a large propor- 
tion of animal food is essential. The amount of protein that can 
be obtained by the common fowl from the coarser vegetable foods 
such as clover, is relatively small, although it is important to 
utilize these foods as far as possible. | 
The natural animal foods eaten by fowls contain usually a high 
percentage of nitrogenous matter and not a large proportion of 
fat. Many of the artificial foods, except such as dried blood and 
skim-mik, contain usually, besides the nitrogenous matter, a high 
percentage of fat, which often is not especially desired in com- 
pounding the ration. [or instance, both earth worms and grass- 
hoppers contain nearly ten times as much protein as fat, while 
ordinary fresh-cut bone contains about equal amounts of protein 
and fat. 
CONDITIONS OF THE EXPERIMENT, 
During two years a number of feeding experiments have been 
made in growing fowls on rations containing greater or less pro- 
portions of animal foods. Those experiments in which rations 
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