THE BREEDING OF CHICKENS 149 



coiisi(!ei';il)k' amounts, siicli as yclluw curii ami urccii f('c(l, 

 iniu'lit have tlic a])])earancc (jf layiiit;- so far as ])i.u;ineiit is 

 concerned thoiiijli slie had nc\ci- ])ro(hice(l an em^. The 

 character of the feed the hen has heen recei\'iii,i;' shonld 

 therefore ahvays he ctuisidci-ed In rehition to hei' condition 

 with reference to ])ia;]nent. 



AYlien hens iiave feeds carrying- an ahnn(hince of ])itiinent, 

 and tlie skin, shanks and beak are not normally ])alc as in the 

 English lireeds. Palmer and Kem]>ster^ ha\e shown tliat the 

 heginning of laying diverts all the pigment recei\cd in tlie 

 feed from other ]^arts of the hody to the ovary wlicre it finds 

 its way into the deveIo])ing yolks. The pigment of the 

 external i)arts gradually disapjiears as a result of the natiu'al 

 physiological change in the structure <if the skin. It is iKit 

 replaced according to these inxcstigators, as hmg as the 

 individual contimies to lay. 



The \'ent loses its pigment \ery (piickly so that a white or 

 pink vent in a. yellow skinned \arii'ty usually imlicatcs that 

 the bird is laying, while a yellow \cnt indicates that she is 

 not laying. 



The eye-ring formed by the iimcr edges of the c> e-lids 

 loses its pigment a trifle slower than the A'ent. The earlobes 

 of the Mediterranean breeds bleach out somewhat n:ore 

 slowly than the e>'e-ring so that in these breeds a white ear- 

 lobe on a vigorous liird usually' means that kn ing has been in 

 progress longer than does a bleached vent or eyelid. 



The color disappears from the beak beginning at the base 

 and remaining longest at the ti]). The lower beak bleaches 

 more rapidl>' than the upper one. AVith the a\eragc yellow 

 skinned bird a bleached beak means that la\ing has been 

 in progress for from four to six weeks. 



The shanks are tlie last to lose their <-olor. iilcaclicd 

 shanks therefore indicate a much longer period of ])roducti<in 

 than does the Ijleaeliing of the other parts. The ])igment 

 disappears from the front of the shank first and finally from 

 the l)ack. A bleached shank usually indicates a, continued 

 egg production for at least fifteen to twenty weeks. 



' Journal of Biological Chemistry, vol. xxxix, No 2. 



