Abstract A MAJOR factor in the cost of production of chicks is the excessive loss of eggs which fail to hatch. It has been estimated that approximately 30 eggs of every hundred placed in commercial incubators fail to hatch. Approximately one half of the eggs which have to be discarded are infertile while the remainder represents eggs in which the embryos for various reasons have died during incubation. It is with this group of eggs, the ones that fail to hatch, that this study is concerned. This investigation was undertaken to determine to what extent, undesirable characteristics found in certain eggs affect hatchability and to obtain information as to the numbers and distribution of such eggs. REVIEW OF LITERATURE Knox and Olsen (1936) studied the effect of tremulous air cells on the hatchability of eggs. They found that eggs 1–7 days old with tremulous air cells gave a hatchability of 56.7 . . .