THE PROBLEMS IN MATING AND IN EGG PRODUCTION 133 



So long as we mate so as to create a group of half the blood 

 each of groups 1 and 2, we have a reservoir of blood to mate 

 back to the two lines of l^lood we have chosen for our line 

 breeding. These groups are the invigorating well of blood 

 that sustains our flocks for all time. "When we create a pen 

 of half-bloods in our own yards we have that which renews 

 the energy and vigor of both numbers 1 and 2 strains, while 

 if we go out of our flock for new blood it serves only to invigor- 

 ate the one, being our male line, number 2. 



Our male line should never be crossed by sex, only as we 

 would create a line representing number 1, or the female line 

 as in our chart; where we used male birds from 6 and 9 to 

 establish the strain of the females, we used in our first cross 

 that produced group number 3. 



While we Ifave made three matings to produce the half- 

 blood cross for numbers 3, 7, and 11, yet the blood in all three 

 is identically alike, being half the blood of each of numbers 1 

 and 2, male and female. In all other groups the percentage 

 of blood differs as per the amount we increase the blood of the 

 two strains we employed. 



To line breed is simply, in all our matings, to get a prepon- 

 derance of the blood we desire to maintain; we have produced 

 these flocks to full blood of the sire in group 8 for the male 

 line and in group 6 for the female line. 



If one wishes to preserve his flocks in one shape, color, and 

 vigor, his line of sires should never be broken (see black lines 

 of the chart). 



Let us suppose a cross were carelessly made. Suppose you 

 mate numbers 15 and 17, and, being pleased with the chicks 

 in 16, you again mate numbers 10 and 12, and again 9, 13, 

 and 18, where would you be? Every chick would be half- 

 bloods, and you are forced back to the old cocks or to intro- 

 duce new blood to get you out of the trouble. 



The whole art of line breeding is to not make mistakes, and 

 to keep each strain of family alone and to each year create a new 

 reservoir of blood. 



Halpin's inbreeding experiments show a rapid decrease in 

 fertility and hatchability. The ratio ran as follows: Inbred 

 first generation, 67 per cent, fertility; second generation, 49 



