Till-: MoLTiXG OF Fowls. 



403 



a hen will eat much more food while in heavy laying than when not in 

 production. In contrast to this, the new coat of feathers, produced 

 in about one-fourth of a year, contains one-fifth as much nitrogen as 

 her body, and one-tenth as much nitrogen as her yearly egg product. 

 Since the increase in body, and the production of eggs, demand an 

 increased supply of food, we may safely conclude that the renewal of 

 plumage will require a liberal, easily digestible food supply, presumably 

 rich in nitrogen; especially so when the molt comes at the end of an 

 • exhausting period of production. 



It is worthy of note in this connection to compare the amount of lime 

 found in the flesh, the eggs, and the feathers of the average 100 Leghorn 

 fowls. (Table IX.) While the feathers do not appear to contain any 

 considerable amount of lime, the eggs, on the other hand, contain about 

 ten times as much mineral matter as the body of the fowl. There 

 appears to be about 13^ pounds of mineral matter in the bodies of 100 

 Leghorn hens and 125 pounds in the eggs which they normally produce. 



Table IX. — Estimated Nitrogen and Mineral Matter in the Body, 

 Feathers and Eggs per 100 Fowls. 



This table was computed on the first 13 periods of the experiment, 

 covering a period of 364 days. It was assumed that the hen shed and 

 replaced her entire plumage once in this time. The quantity of feathers 

 per hen was estimated at 4.53% of the total weight of the fowl.* Only 



* Theses on " Comparative .Anatomy of Various Breeds of Fowls to Show Type 

 Differences," by C. A. Rogers and H. C. Pierce, Cornell University, 1905 and 1906, 



