130 MAINE AGRICULTURAL EXPERIMENT STATION. IQII. 



It would be highly desirable if records could be presented for 

 the hatching of eggs and the mortality of chicks during the 

 whole period covered by the mass selection experiment. Un- 

 fortunately it is impossible to do this since no such records were 

 kept prior to the hatching season of 1908 (laying year 1907-08). 

 Data on these points have been kept since that time, however. 

 The figures for the hatching seasons of 1908 and 1909 have 

 already been published.* For comparison with these, and to 

 serve as a basis for a discussion of the present condition of the 

 stock, in respect to these matters and in relation to the method 

 of breeding now being followed, similar data will be given here 

 for the hatching season of 191 1 (laying year 1910-11). 



Tables B and C give the hatching records for the season of 

 191 1 for birds belonging respectively to high and low fecundity 

 lines. All of the birds in Table B belong to pedigree lines in 

 which the mean winter egg production of all females for four 

 generations has been high. These are the birds used in 191 1 to 

 propagate the "high lines," the egg production of which is disr 

 cussed farther on. All of the birds in Table C belong to pedi- 

 gree lines in which the mean winter production has been uni- 

 formly low for four generations. . The females in these two 

 tables represent of course only a part of all birds bred in 1911, 

 but they are the only ones whose hatching records are perti- 

 nent to the present discussion. Cross-bred birds and Barred 

 Rocks in other lines of experimentation do not concern us here. 

 As a matter of fact, the averages of Table B represent about 

 the average hatching and rearing record of all birds bred in 

 1911. Some groups of birds did conspicuously better, especially 

 on the rearing records. 



* Pearl, R. and Surface, F. M. Studies on the Physiology of Repro- 

 duction in the Domestic Fowl. IV. Data on certain Factors Influencing 

 the Fertility and Hatching of Eggs. Ann. Rpt. Me. Agr. Expt. Stat, for 

 1909, pp. 105-164. 



