The experiments were commenced in the summer of 1906 and were 

 reported upon in the Annual Report of the College. The experiments of 

 1906 indicated that a hen was a better hatcher than an incubator, and 

 that so far as we had learned, she differed from incubators in having - less 

 evaporation of the egg content, and in having- a much higher amount of 

 carbonic acid gas in the air immediately surrounding the eggs. Last 

 year we kept no detailed record of the mortality of the chicks. The July 

 and August chickens lived and grew fairly well. This may have been 

 due to the fact that the machines of 1906 were washed with a solution of 

 zenoleum, mainly for the reason that they then looked cleaner and had 

 less of the incubator odor. We thought the good results obtained were 

 due to the fresher air of the incubator room, but as the same room and 

 many of the same machines were used this year, we cannot maintain the 

 idea as being- correct. 



We have this season tried to make the conditions in the machines 

 more like those found under the hen. It will be noticed in the tables that 

 we have operated nearly all the makes of incubators, at times, different 

 to the manufacturers' directions; hence, one should not judge a machine 

 by these results. 



Eggs Used for Hatching. 



It is a well known fact that eggs vary in their power of hatching. 

 Some eggs are infertile; some are fertilized, but the germ is so weak that 

 it dies early in the period of incubation ; others reach practically the hatch- 

 ing stage and then die. The power of hatching is influenced by breeding, 

 feeding, housing, etc. Where one proposes to follow the vitality of chicks 

 or even to consider any phase of the incubation or rearing problems, it 

 becomes necessary to have eggs as nearly alike as possible ; hence, we 

 have used in nearly all the experiments, eggs laid by the same individual 

 hens. We have been trap-nesting over 500 hens and have used such eggs 

 en this work. We have also used shuffled eggs which were pur- 

 chased from outside sources. By shuffled eggs is meant, simply, a com- 

 mon box or basket of eggs such as would be gathered from an ordinary 

 flock. 



The tables which follow give the results obtained from the individual 

 eggs, with the exception of the mortality column, which gives the mortality 

 of the chicks from all sources. The results obtained from the shuffled 

 eggs are omitted for the reason that we failed to get anywhere near an 

 equal division of the eggs as to fertility, etc. We regret that the results 

 should be so. We tried many methods of mixing and separating the 

 eggs with the results as above mentioned. The mortality of the chicks 

 from both kinds of eggs was very nearly the same ; therefore, there was 

 no necessity of separating the deaths from each kind of eggs. 



If the method of incubating has no effect upon vitality, and the same 

 hen's eggs are in each machine, then the chicks should live in nearly the 

 same proportions, provided that the brooding, feeding, and care are the 



