INCUBATION OF THE EGG OF THE COMMON FOWL. 365 



teristic lateral movements. Sometimes there are so many eggs 

 in the nest or they are so widely scattered that the hen fails to 

 properly cover them. When such conditions occur, the hen 

 invariably uses her beak to bring the outlying eggs in contact 

 with her body. Not only does she frequently thus turn the 

 eggs, but also she very often reaches beneath her body and 

 turns the eggs lying near the center of the nest. Why she does 

 this is a question which awaits an answer. 



Experiments. Seventy-five eggs were selected from three lots 

 of fowls, arranged in three groups and so placed that the eggs 

 from one lot of fowls alternated with those from another lot. 

 Those eggs of group I. were left unmoved ; those of group II. 

 were turned at 6 A. M., and 6 P. M.; those of group III. were 

 turned at 6 A. M., 9 A. M., 12 M., 3 P. M. and 6 P. M. 



From group I., five infertile eggs were removed on the fifth 

 day, together with eight dead embryos, six of which had grown 

 fast to the shell membrane. The eggs were again examined 

 on the twelfth day and five more dead embryos were removed. 

 These were examined and four were found to have the allantois 

 grown fast to the yolk ; but three chicks hatched from the entire 

 twenty-five. The remaining four were dead in the shell. The 

 number hatched was 15 per cent, of the fertile eggs. 



In group II. there were three infertile eggs removed on the 

 fifth day, and one dead embryo which had adhered to the shell 

 membrane. On the twelfth day four dead embryos were removed, 

 one had the allantois adhering to the yoke. In the others the 

 cause of death could only be surmised. From the remainder, 

 ten chicks were hatched ; the others died in the shell, giving a 

 hatch of 45.4 per cent, of the fertile eggs. 



In group III. six infertile eggs were found on the fifth day and 

 no dead embryos. On the twelfth day one dead embryo was 

 found. Eleven chicks hatched; two died after having pipped, 

 while the remaining five were dead in the shell ; the number of 

 hatched chicks being 58 per cent, of the fertile eggs. The ex- 

 periments indicate that frequent turnings (at least five) give best 

 results. 



It is necessary to point out, however, that a very low percent- 

 age of chicks hatched even in group III. This is to be attributed 



