The time between egg laying and hatching depends on the species. As a general rule, the bigger the bird, the longer the incubation period. Some species of white-eye and cowbird hatch only 11 or 12 days after laying, while a wandering albatross egg is brooded for about 11 weeks, with the parents working in shifts to keep it warm.
The incubation period for an emperor penguin egg is shorter at two months, but the male must perform incubation duties alone in perishingly cold conditions and loses about a third of his body weight.
Some birds don’t start incubating until all the eggs are laid so that they all hatch together, but it means the egg laid first takes longer to hatch. Others commence incubation as soon as the first is laid, resulting in the eggs hatching in sequence.
Chicks, too, have some control over timings. Quail chicks can communicate with each other while still inside their shells in order to synchronise hatching.
And some birds don’t physically incubate their eggs. The chicken-like megapodes, such as the Australian brushturkey, instead bury them in specially built mounds of earth, which are packed out
with vegetation that produces heat as it decays.