CONTENTS. 



PAGE 



Introduction ............ 99 



The working hypothesis .......... 99 



Plan of procedure ........... 103 



The foundation stocks . . . . . . . . . 103 



Basis of selection of breeding females ...... 103 



Basis of selection of breeding males ....... 105 



Continued use of breeders on the basis of the performance of their 



offspring ........... 106 



Points in management that affect the results ..... 106 



Seasons at which increased production is most desirable . . . 108 



Results secured ........... 109 



Changes in mean winter egg production . . . . . .111 



Changes in mean annual production . . . . . . .112 



Changes in daily winter production . . . . . . .113 



Changes in age at which first egg is laid . . . . . .114 



Changes in length of the initial cycle and its complement, the winter pause 115 

 Changes in amount of broodiness . . . . . . .117 



Changes in date of last egg . . . . . . . .118 



Changes in rate (intensity) of production ...... 120 



Changes in seasonal distribution of production ..... 120 



Changes in variability ......... 123 



Influence of changes in sanitary methods ...... 123 



Recommendations ........... 123 



Summary ............ 124 



Literature cited ........... 125 



