1921.] 



Recent Research in Egg Production. 1027 



broodiness and the period occupied in moulting, but on these 

 points, so far as the writer is aware, no research has been made. 



Goodale( 22 ) has shown that individuals of a breed show 

 considerable variation in broodiness, and that the tendency 

 to go broody increases with age. Broodiness is also dependant 

 on the time of year and the temperature, but no effective 

 methods of preventing it have yet been found. 



Research on the effect of broodiness on egg yield and the 

 physiological causes of the broody condition would appear to 

 afford promising results. 



Breed Variation. — Numerous breed trials and tests have 

 taken place in most countries, but only a few need be quoted 

 here. 



Three-year tests made at Copenhagen show the following 

 order of merit of breeds as regards production of eggs: — Leg- 

 horns 100, Plymouth Rocks 70, White Wyandottes 60. 



Lewis( 23 ) quotes tests in the United States to show that the 

 average number of eggs laid per bird per year was approxi- 

 mately as follows: — Leghorns 170, Plymouth Kocks 155, Rhode 

 Island Reds 150, Wyandottes 144. 



Laurie ( 24 ) in South Australia found that the average yearly 

 egg production per bird in the various breeds was as follows : — 

 White Leghorn 199, Orpingtons 170, Wyandottes 170. 



It is possible, however, that English strains of these breeds 

 would not hold the same relative positions as regards fecundity. 



The Irish winter egg record tests ( 25 ) (October to March) for 

 the seven years 1908-1915 show the following averages for the 

 different breeds : — White Leghorns 49-5, Rhode Island Reds 

 45-9, White Wyandottes 35-8, Plymouth Rocks 32-9. 



These records also show, however, that there is much greater 

 variation in the different strains of a breed than there is 

 between breeds; thus the best pen of White Leghorns averaged 

 (October to March) 84 eggs, while the worst averaged 31 eggs, 

 and the best pen of Plymouth Rocks averaged 55 eggs, while 

 the worst averaged only 15 eggs. W T ithin any breed there 

 appears to be much room for improvement along the lines of 

 inheritance of high egg production through the cock, as has 

 been demonstrated by Pearl. (!) 



Ball and Alder (4a) have shown that breeds differ in the time 

 of year at which the highest rate of egg production takes place. 



(22) Anat. Bee, No. 6, 1917. 



(23) Neiv Jersey Sta., Hints to. Poulirymen, No. 4, 1918. 



(24) Bui. Int. Inst. Aqr.. Borne, II., 1914, p. 1400. 



(25) Dept. Agr. and Tech. Instr. for Ireland, Vol. 15, No. 3, 1914-1915, p. 592. 



