49 POULTRY CULTURE 



habit of the turkey makes it quite possible for females and males 

 from different flocks to mate without the knowledge of the keeper. 

 There is no authentic instance of the influence of impregnation con- 

 tinuing as long as three weeks in fowls. When birds of different 

 varieties that have been running together are separated and mated 

 each with its own kind, no effects of previous matings are likely to 

 appear after a week or ten days. 1 The usual rule is not to use the 

 eggs for hatching until two weeks after separation. 



Regulation of sex. It would be a decided advantage to many 

 poultry keepers to be able to control sex, but there is no known 

 method of either controlling or influencing the proportions of the 

 sexes. Usually they are produced in nearly equal numbers, even 

 in small broods. Occasionally one sex will greatly predominate in 

 a brood, in a small stock, or in the offspring of a particular mating. 

 Current reports sometimes indicate a general preponderance of 

 one sex in a particular season, in which case every one with a theory 

 on the control of sex can easily find instances which seem to con- 

 firm it. When the preponderance of one sex is quite general, it 

 suggests that some general condition may influence sex. If so, any 

 general control of sex by the breeder is plainly impossible. On such 

 scant and crude observations as have been made on this point, the 

 only instances of regularity in predominance of numbers of one 

 sex are found in particular matings or in individual birds. 2 In 

 none of these cases did the tendency to produce one sex appear 

 to be transmitted. It is possible that the occurrence of a large excess 

 of one sex was purely accidental. 



1 It does not seem to me necessary to say more on the subjects of contamina- 

 tion and telegony than is said above, except to add that in a considerable experi- 

 ence with different kinds of poultry I have never seen a trace of contamination 

 from eggs set two weeks after separation from a male 'of another variety, and that, 

 although ever since 1897 I have made it a point to take up every case of mental 

 impression reported to me, in not a single instance has a person reporting such 

 cases been willing to answer questions or to have the case investigated. 



2 The most remarkable cases I have known or heard of were the following : In the 

 early nineties I had a Houdan male that for two seasons mated in four different mat- 

 ings, once with Houdan hens, once with Light Brahmas, once with Barred Plym- 

 outh Rocks, and once with Brown Leghorns, produced regularly about five pullets 

 in every six chickens. Mr. A. C. Smith informed me that the celebrated Barred 

 Plymouth Rock male Rally produced the sexes regularly in about the same ratio, 

 five females in six chicks, a quality in his case decidedly objectionable, the 

 daughters of an Exhibition Barred Rock male being useful only for breeding. 



