28 BOARD OF AGRICU.LTURP:. [Pub. Doc 



may the next year, as mature fowls, be used in the breeding 

 pens to produce more and better of their kind. Prepotency 

 pays in poultrA' breeding. It signifies extra strong power in 

 transmitting (juality to otispring ; and by mating together 

 fowls having the i)Ower along the lines of egg production, 

 early and large flesh development, or beautiful shape and 

 attractive plumage, offspring are secured which have enhanced 

 value along these lines, and intensified power in reproducing 

 the same in their })rogeny. 



Incubation. 



The subject of artificial hatching is too large to allow of 

 treatment here, but one or two hints may at least be given. 

 Late experiments and experience with hatching machines 

 emphasize the desirability of restricted ventilation, or the 

 supplying of abundant moisture in the air of the egg chamber 

 during the first week of incubation. Either or both of these 

 precautions tend to aid normal rational development of the 

 embryos during the early stages. On the other hand, abund- 

 ant ventilation, and, if necessary, daily airing of the incubat- 

 ing eggs during the latter half of the incubating period, tends 

 to healthy, regular growth of the chicks in the shells and 

 to safe hatching of vigorous broods of birds. 



The very opposite of these conditions too often prevails, 

 and the results include hemorrhages, shown by ' ' blood rings " 

 in the eggs ; enlargement of the heart and blood vessels, 

 indicated by large and very bright scarlet veins ; a sharply 

 defined body and very dark " eye spot," as seen in the light 

 of the eofof-testcr. The "blood rinsf" is the simi of death. 

 The sharp, distinct outline of the embryo and the bright 

 scarlet blood vessels indicate excessive development of the 

 circulatory system, from which later there is a reaction, indi- 

 cated by sluggish development towards the end of incuba- 

 tion, death in the shell, or failure to hatch even after the 

 shell is pipped. If the chicks do hatch, they are very likely 

 to be weak, to mope about, to "hug the heat" and huddle 

 under the hover of the brooder, to have little appetite, and 

 in spite of th(^ [)oultryman's care to give up the struggle 

 within ten or twelve days after hatching. When too high a 

 temperature or "hot spots" in the incubator chamber add 



