so THE AMERICAN BREEDS OF POULTRY 



was found to have 2,306 had a winter production of 3 eggs. Almost 

 any female will carry enough minute yolks to theoretically make a 

 200-egg hen for five successive years. What is it then that gears hens 

 up so that they will mature a larger number of these yolks and lay a 

 larger number of eggs? The answer is a factor that represents high 

 production which the bird must inherit. 



There is a distinguishable difference between low production or less 

 than 30 eggs during the winter months, and high production or more 

 than 30 eggs during the winter months. Let us observe how high 

 producing pullets have actually been bred from low producers. The 

 hen that has a winter egg yield of less than 30 eggs is a hen and has 

 an ovary and H will stand for her. She lays some eggs and E will 

 stand for this character. The hen that lays less than 30 eggs may 

 therefore be designated as HE. Now, if a hen is to be a high layer, 

 a new factor is necessary in the germ plasm. Let IGHT stand for 

 this new factor. The low producer inherited and possesses two fac- 

 tors H and E, while the high producer inherited a supplemental factor 

 IGHT which raises the first two factors, hen and eggs, to HEIGHT 

 of egg production. 



At the Maine Station where the breeding experiments were carried 

 on, it was found that females may possess all these factors and be 

 high producers, yet they can transmit to their pullets only the first 

 two, and the determining factor for high production must be possessed 

 and transmitted by the male. Accordingly it was found that a prop- 

 erly bred and fully possessed male would grade up a low producing 

 flock in a single generation. The factor for increased production is 

 not present in all males and being an invisible hereditary cell, its pres- 

 ence can only be determined by experimental breeding of the individual 

 itself. Chapter IV will hold out some help to the breeder in pick- 

 ing his birds for egg production according to easily distinguished 

 somatic characters; nevertheless, the experimental evidence on the 

 inheritance of fecundity is as valuable as it is interesting in showing 

 that inheritance for high production is not from dam to daughter but 

 from sire to daughter, and therefore a poor male mated to high 

 producing females will decrease the production of the pullets for 

 they depend upon their sire for the inheritance of the excess produc- 

 tion factor. 



The lesson to be learned. A conception of the fowl not as an 

 indivisible whole but as a composite whole made up in an orderly 

 and consistent manner of different parts which behave and are trans- 

 rnitted as factors, gives rise to several important subjects. First, a 

 bird may be purebred in respect to one character and not pure in 

 respect to another. Blue color in chickens, for instance, is never 

 pure, which is to say that blue chickens always produce some black 

 and some splashed white chicks. Such a bird while not pure for 

 blue color may be pure in respect to other characters; for instance, 

 comb. Second, on figuring transmission the old wav which was as 



