The king penguin and emperor penguin build no nests at all. They keep their eggs or small chicks warm under a fold of their belly, holding them on the tops of their feet. A pair of male and female penguins may nest together every year for many years. The female usually lays one or two eggs. Penguin eggs take from 30 to 65 days to hatch.
Larger species take longer to hatch and to grow.
Both parents take turns searching for food and caring for the eggs. The parent at the nest does not eat while the other parent is away, sometimes for a month at a time or longer. When a chick hatches, the parents must guard it until it is strong enough to defend itself. It remains near the nest for the first 2 to 12 months of its life, depending on the species. The chick is covered by downy feathers that are slowly replaced by mature ones.