Like other birds penguins shed their worn – out feathers and grow new ones each year. The rigors of breeding and constant preening, subject a bird’s plumage to considerable wear and tear. Feather must be replaced each year – usually after the nesting season.

This process is called molting. For many birds, molting happens slowly. It may even be hard to notice that they are molting.

Molting is a big problem for penguins, however, when they lose their feathers, they lose their waterproof protection. They can not go in the water to feed until new feathers have grown in.
Before molting, penguins swim out to sea and eat as much as they can. Then they wait.

Soon the penguins’ old feathers start falling out in clumps. Molting take place gradually over several weeks so that the bird retains sufficient feathering to keep warm. However, penguins lose their waterproofing so they must stay ashore until the molt is complete. During that time, the penguins do not eat at all. By the time their new feathers have grown in, the birds have lost half their body weight.

During the year the feathers become badly worn by so much swimming and diving in the salt sea water, by countless leaps ashore and back into the water, by sliding games on the ice, by wind and sun, rain and snow. Before nest winter comes, the plumage must be warm, thick and smooth again. So now, in summertime, the old feathers fall out in bunches, and underneath, the spotless, shining new feather suit is already growing. In this feather- growing period, which takes two to three weeks, the “non – breeders’ simply stand around, doing nothing. They can not go out in search of food until their new coats are watertight, or they would freeze to death in the icy water.

Penguins lose all of its feathers and replace it once a year.

Chicks in the process of shedding their coats of down to reveal the adult plumage. This occurs by January, just after midsummer, when they leave the rookeries to fend for themselves.