148 POULTRY PRODUCTION 



Lewis' lias also calciilatoil tlie average p*-'i' t'ciit egi;' produc- 

 tion for earh month from the records of all the laying contests 

 in American during the years 1912 to llUO, inclusive. The 

 result of his calculation is shown in Tahle X\ III. 



TABL^;X^■1II, — The Average Per Cent of Perfect I'iioduction Duking 

 THE Diiieue.\t Mo\ths OF THE Ye\hs 1912 TO lyiS IxiLr^^IVK FOR 

 All of the Layi.\g Contests in A-meuica. (Piust Laving 'i ear (.InlyJ 



Indications of Laying.- — In order to lay well a hen must iirst 

 of all he sound and A'igorous. The chara.cteristics of a. 

 A'io'orous fowl ha\'c already heen descnheil. There are, 

 however, further indications of laying not necessarily associ- 

 ated \\\\\\ \'ig(ir. These are pigiiieiitatinn, hody ehanges, 

 molting and tcm]:)cra,ment. 



l''i(jrnniiation.~\i\ those \-arieties showing yellow pigment 

 in the siilicutaueous fat, shanks, and earlohes (in those 

 varieties having the so-calle(l wdiite earlohe), the ingment 

 tends to disappear as laying progresses. Palmer' has shown 

 that the jiresence or absence of this pigment in the fowl or its 

 eggs is <lirectly correlated -with the ])resence or absence in the 

 feed of a earotinoid p^igment called xantho])hyll. For this 

 reason a hen fed on a ration devoid of feeds which carry it in 



1 .lour. Aui. .\ssn. Ins(. and In\-est. in I'oiil. Husb., vol. v, Xo. 5. 



2 This arruunt is adapted and slightly aniplihcd from the one adopted 

 at the judging school held at Cornell University July, 1918, and approved 

 by the Anii-riean Association of Instructors and Investigators in Poultry 

 Ilusliandiw and published in its journal, vol. v, No. 1. 



^ .lournal of Biological Chemistry, \o\. xxiii. No. 1. 



