1921.] Recent Research in Egg Production. 1023 



Pearl. Pearl found also that the difference between a high- 

 producing and a low-producing hen did not depend on the 

 number of oocytes in the ovary, but on the number which 

 developed, and that this quality was inherited in the fowl. 

 He further discovered that the best measure of the capacity 

 of a hen to produce eggs was the number of eggs produced 

 during the winter months; hens which laid well at that time 

 produced the greatest number of eggs in the year. 



Selection of Hons. — Several investigators have given atten- 

 tion to the problem of the early identification of a high- 

 producing hen, so that the unproductive layers may be weeded 

 out with a minimum of delay. Blakslee and Warner( 3 ) found 

 that when birds with yellow pigmented skin, ear-lobes, 

 beak and legs (as in Leghorns, Plymouth Rocks and 

 Wyandottes), begin to lay, the yellow colour disappears from 

 the ear-lobes, beak and vent, in the order named, probably 

 being transferred to the yolk of the egg. When laying stops 

 the colour is regained in the same order. This result was 

 taken as a test for the unproductive hen, and it is found that 

 the greater the amount of yellow colour in the ear-lobe the less 

 active is the laying. 



Chard( 4 ) has found that the high producers of one year con- 

 tinue to be the high producers during the second year, and 

 that all the birds selected for high production during the months 

 of November, December and January gave high records for 

 the whole year. 



Ball and Alder( 4a ) also found that the more eggs hens pro- 

 duced in the year the greater was the proportion laid during 

 the winter period ; so that the breeding and keeping of hens 

 of high productivity has the double advantage, in that not 

 only are more eggs produced, but that they are produced at 

 a time of scarcity and so command good prices. Wilson ( 5 ) has 

 discovered that a hen's total yield for the year can be pre- 

 dicted from her performance during the first eight or ten weeks 

 of the laying season (November, December and January). 

 Good layers produce durinp- this period a<< many as five eggs 

 per week, while bad hens yield few. if any. 



Chard*' 4 ) also noticed that the production of eggs was closely 

 dependent on the temperature, and this is probably the under- 

 lying cause of the variations in productivity- that exist at 



(3) Utah Sta. Bui., 1917. 



(4) Connecticut Storrs Sta. Bid., 1917. 



(4a 1 ) Jour. Amcr. Assn. Instr. and Invest. Poultry Husbandry, No. 5, 1917. 



(5) Jour. Dept. Aqr. and Tech. Instr. for Ireland, Vol. 14, p. 271. 



c 2 



