Embryonic Mortality in the Fowl

MALPOSITION III (head under left wing) is probably the most important malposition because of its frequency, which may range up to 5 percent of the embryos still alive after 18 days of incubation, and the fact that it is almost always lethal. Its cause is quite unknown, except that it is more frequent in eggs incubated with the large end up than in those incubated horizontally (Byerly and Olsen, 1936). During examination of some 40,000 unhatched eggs it appeared to the writer that malposition III was more frequent in the larger eggs, and, since definite information on this point was lacking, an investigation was undertaken to determine the relationships, if any, between the frequencies of various malpositions of the embryo and the size and shape of eggs. MATERIAL AND METHODS During 1933 and 1934 all eggs incubated in the regular hatches at the Minnesota Agricultural Experiment Station were utilized. The . . .