In the 2006 film Happy Feet, the protagonist Emperor Penguin, Mumble is half-covered with baby fluff in the final version. In earlier versions, he was to moult completely. This was likely changed so he could be more easily identified.

Pictures of Adult Mumble can be found in these Happy Feet books.

And they can also be found on this page:

Here are some pictures of the fluffy Mumble and below them are the pictures of the Adult Mumble.