Effects of Different Temperatures in the Incubator on the Prenatal and Postnatal Development of the Chick

Abstract

FOR many years the prevailing practice in the operation of sectional-type incubators (without forced-draft) has been to raise the temperature toward the end of the incubation period. Philips (1916) stated, as a result of his studies of various levels of temperature, that “a temperature of 101°, 102°, and 103°F. for the first, second, and third weeks respectively . . . will prove very satisfactory.” After further studies, however, Philips and Brooks (1923) concluded that the optimum temperature was between 100° and 103°F. The validity of this practice had till recently not been questioned, presumably because Eycleshymer (1907), Simpson (1911), and Cadman (1923) had all found that the temperature of the sitting hen rises when the eggs are hatching. The temperature of the nest is subject to such great variation due to the movements of the hen, particularly at hatching time, that it cannot be measured precisely. However, since the temperature . . .