PRAIRIE FARMER'S POULTRY BOOK 



up the egg is getting too much moisture. Cloudy eggs are 

 defective and indicate a breaking up of the egg contents. 

 Other defects will appear, and with a little practice the operator 

 will soon learn to detect the eggs with strong germs. 



The By-Products 



It is claimed that the great packing establishments in Chi- 

 cago make their profits largely on the by-products. Every- 

 thing is saved and utilized — the hair, blood, viscera, bones and 

 excreta. Some of the manufactured goods are bone meal, gran- 

 ulated bone, meat scrap, meat meal, tankage, blood meal and 

 fertilizer. ^ 



The chief by-products of poultry are the feathers and the 

 fertilizer. 



Feathers 



What is a feather? It is a modified scale, being derived 

 from the skin, or epidermis. The types of feathers are the 

 perfect, the downy and the hairy. The hairy type is illus- 

 trated in the hairs that remain on a fowl after plucking and 

 which are usually removed by singeing. Down is the tj'pe 

 of feather found in the day-old chick and upon ducks and 

 geese after the outer feathers are removed. The perfect type 

 is developed after hatching and is described below. 



The structure of a feather includes the following parts : 



Quill, the naked hollow barrel which is inserted into the skin. 



Shaft, which is a continuation of the quill. It is rectangular in cross- 

 section. 



Vane, the expanded portions of the feather attached to the sides 

 of the shaft. 



The vane consists of the barbs, which are branches from the shaft; 

 the barbules, branches from the barbs; and barbicels, branches from the 

 barbules. The barbules and barbicels have booklets by means of which 

 these structures are interlocked. Thus, by these overlapping and inter- 

 locking parts, the vane, or web, is formed. This makes the feather very 

 resistant to air in flight. 



Composition of a feather. The feather is composed of a 

 large percentage of silica. The organic constituent consists 

 approximately as follows : Carbon, SO per cent ; hydrogen, 6 

 per cent; nitrogen, 17 per cent; oxygen, 23 per cent; sulphur, 

 4 per cent. 



The abundance of nitrogen in the composition suggests the 

 importance of a nitrogenous diet during the molt. 



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