WINTER CYCLE AND WINl'ER PAUSE ^g^ 



to lay at the same age, yet the first showing a distinct winter pause, places 

 the difference in the groups as inherent. Such a study within the family 

 gives definite ratios of panose and non-pa>ise pullets as Hays (1P24) 

 points out. 



The line of deinarkation between genetically non-pause birds that exhibit 

 winter pause due to environmental influences and birds carrying the dominant 

 factor (M) for pause cannot be drawn. The present paper is devoted to a 

 consideration of the non-heritable and some heritable factors that may or 

 may not affect winter cycle and winter pause. Genetic factors concerned 

 with the inheritance of winter cycle length and winter pause duration have 

 not been dealt with. 



The major teachings of this study may be summarized: 



1. In general, early-hatched jnillets have a longer laying cycle than late- 

 hatched pullets of the same flock. 



2. Date of first egg exhibits a rather intimate negative correlation to 

 length of winter cycle. 



3. Age at first egg shows an appreciable negative correlation to length of 

 winter cycle. 



4. The winter egg record is intimately positively correlated with length of 

 winter cycle. 



5. Annual egg production is significantly correlated with length of winter 

 cycle though less intimately than is winter record. 



6. A minor though significant degree of negative correlation appears be- 

 tween length of \\inter cycle and length of winter pause. 



7. Hatching date bears a significant but not intimate negative correla- 

 tion to length of winter pau.se in the pause population. 



8. Early hatching is positively correlated with the presence of winter 

 pause in the total population of pause and non-pause birds. 



9. Time of beginning to lay is significantly negatively correlated with 

 length of winter pause in the pause population. 



10. Time of beginning to lay is appreciably jjositively correlated with 

 early hatching in the total population. 



11. Age at first egg shows the identical degree of negative correlation to 

 length of winter pause that it shows to lenf/th of winter cycle. 



12. Early sexual maturity is positively correlated witii the presence of 

 winter pause in the total population. 



13. Weight at first egg is independent of length of winter pause. 



14. Light weight at first egg is not correlated with the presence of winter 

 pause in the total population. 



15. The net winter rate of laying holds a very slight negative correlation 

 to length of winter pause in the pause population. 



16. Slow rate of winter laying is rather intimately positively correlated 

 with the presence of winter pause in the total population. 



17. The average size of winter clutch is but \ery slightly correlated with 

 length of winter pau.se in the pause population. 



18. Small size of winter clutch is moderately positively correlated with 

 the presence of winter pause in the total population. 



