All of the penguins have just finished their annual moult. Which only happens once a year. Instead of losing a feather at a time like most birds do, penguins lose all of their feathers over a few weeks and they look very very untidy while they do this. In fact they look quite ill and unkept during this time. However, after a few weeks all of their new feathers have grown back and they look lovely clean and coated in shiny new feathers.