Incubation Requirements

Abstract

When the egg is laid development has already begun. It is then suspended until the egg is warmed again sufficiently. The time between this renewed warming and emergence of the chick (the incubation period) varies between species, and is roughly in proportion to egg size (see, e.g., Bergtold, 1917). In small song birds the incubation period can be as short as 10–14 days, in the domestic fowl it is 20–21 days and it extends to 42 days in a large sea bird such as the gannet (Nelson, 1966) or up to 50 days in the Mallee fowl (Frith, 1962) and the brush turkey (Baltin, 1969) while in the royal albatross it lasts about 80 days.