A robin’s eggs hatch 12 to 14 days after they are laid. Robins lay three to five eggs during their first nesting season, one egg each day until the clutch is complete.
Robins keep the clutch cool before the last egg is laid so the nestlings all hatch at approximately the same time.
Incubating is done mainly by the female, who rarely leaves her clutch for more than a few minutes at a time. She turns and rotates the eggs with her bill several times a day to keep the temperature even and to prevent the nestlings from sticking to the shell. The eggs must be kept warm in order to hatch. The mother robin sits on them and spreads her outer feathers, using body heat to protect her developing clutch.