1921.] Recent Research in Egg Production. 1020 



and the number of eggs laid. The distance from the hind end 

 of the keel to the pelvic bones was thought to be the best 

 guide to laying capacity. 



Effect of Exercise. — In America experiments have been 

 made to compare the egg production of fowls allowed free range 

 with those in confinement. Buss( 28 ) found that exercise 

 increased the production of eggs, and similar results were 

 obtained by Kirkpatrick and Warner. ( 29 ) The latter put up 

 two pens of White Leghorns, each of 40 birds; the first pen 

 was confined and the second had the run of a yard. The fol- 

 lowing table shows the number of eggs laid by the two pens: — 



Weeks of Experiment. 



1st— 13th. 



14th— 26th. 



27th— 39th. 40tli-52iid. 



Total for 



Year. 



Confined 



179 



1.221 



1,589 



1,483 



4.4; 2 



Run in "Yard 



466 



1,285 



2,079 



1,525 



. r >,355 



Size of the Egg. — The size of the egg laid by the hen is 

 undoubtedly a breed characteristic. It was found in the trials 

 at Copenhagen( 14 ) that the average weight of eggs was greater 

 in the Minorcas and Leghorns than in the Wyandottes and 

 Houdans. Kirkpatrick and Card( 3 °) found that the average 

 weight of twelve eggs of various breeds was as follows : — 

 Rhode Island Reds 1-60 lb., Plymouth Rocks 1-58 lb., Leg- 

 horns 1-50 lb., and Wyandottes 1-48 lb. 



Murphy (31) in Ireland, who investigated the inheritance of 

 the size of eggs, found that, when a hen laying a large sized 

 egg was mated with a cock, the son of a similar hen, the pullet 

 offspring invariably laid eggs of large size. In America, 

 also, (32) it has been shown that ability to lay large, heavy eggs 

 is inherited. 



The size of the eggs laid by any hen. however, varies 

 with the time of year. At wood ( 33 ) discovered that the eggs are 

 heaviest from November to April and lightest from May to 

 October; thus a pen of hens in February laid eggs which 

 averaged 12-72 lb. per 100 eggs, whereas the same pen in June 

 was laying eggs which averaged only 11 07 lb. per 100 eggs. 

 A possible explanation of this fact is suggested by Warner 



(28) Ohio Sta. Bid., 1916. 



(29) Pennsylvania Sta. Bcpt., 1914. 



(30) Connecticut Sta. Bui., 1915. 



(31) Dept. Agr. and Tech. Instr.. Ireland. Jour.. Xo. 2, 1917. 



(32) Bui. Rhode Island State College, Xo. 4. 1918. 



(33) West Virginia Univ. Agri. Exp. Sta Bui. Xo. 145, 1914. 



