Lethality of Embryo Malpositions in the Domestic Fowl

APPROXIMATELY one-half of the fertile eggs which fail to hatch in any lot of eggs set contain chicks which have nearly completed development. About half of these, or one-fourth of all the fertile eggs which have failed to hatch, contain chicks in one or more of several malpositions. Thus, in a lot of eggs 60 percent of which hatch, the number of chicks affected by malpositions is about 10 percent of the fertile eggs set. It is obviously of very great economic importance to know to what extent the several malpositions are lethal to the affected chicks. It is the object of the present paper to present new data on the lethality of malpositions and to scrutinize the data and opinions found in the literature. It was supposed by Sanctuary (1925) that malposition1 I is always lethal; he stated that chicks in other malpositions sometimes hatch. Hale (1930) expressed the . . .