SPECIAL FEATURES 181 



for in healthy birds and an increased egg yield. To promote 

 exercise it is well to keep the floor of the laying pen or scratching 

 shed covered to a depth of four or more inches with good litter, 

 and during the winter throw therein at least half of all the feed 

 consumed. 



Digestibility of Ground Grains. — Experiments show that a 

 greater efficiency is obtained from feed consumed if a part of the 

 grains are fed in ground form or as a dry mash. Experiments 

 covering a period of two years show that birds receiving whole 

 grains give a product valued at only 48 per cent above the cost 

 of feed, while those receiving part of the ration in the form of 

 ground grains showed an excess of 68 per cent. The actual differ- 

 ence in the total value of product was found to be about one-third 

 greater with the hens having ground grains in the ration. More 

 energy is required in the digestion of whole grains than ground 

 grains. The exact determination of whether or not it will pay to 

 feed ground grains will depend on the nature of the ration. If 

 too much time and energy are required for fowls to grind the feed, 

 egg production will be retarded; but, on the other hand, if all 

 grains are fed ground, exercise will be restricted and the health of 

 the birds impaired by reason of the tendency toward too great a 

 concentration. This undue stimulation to an unnatural egg yield 

 is likely to result in lowering the bird's vitality. 



Mineral Matter for Laying Hens. — The ash content of different 

 feeds varies considerably, and the bird's requirements also vary 

 during the different periods of its life. The problem is to adjust 

 properly these varying factors to each other. During the growing 

 stage and during egg production, more ash is required than is 

 supplied by the ash content in vegetable feeding stuffs. Wheat 

 bran is very rich in digestible ash, and is easily adapted to the 

 feeding of baby chicks, but it does not supply enough to meet 

 the requirements of laying hens. The lack of ash in the ration 

 of laying birds tends to induce egg eating, because soft-shelled 

 eggs are then likely to be produced. This condition can be pre- 

 vented by keeping crushed oyster shell, ground bone, and similar 

 material constantly before the hens. The shell constitutes 8 per 

 cent of the whole egg, and to lay 160 eggs in a year the hen will 

 require 1.6 pounds of mineral matter for the shells alone. 



Use of Sharp Grit. — Birds have no teeth with which to grind 

 feed, this mastication being performed in the gizzard by muscular 

 action. In order that this work may be properly done, sharp grit 



