Plumage
Plumage is defined as "The entire feathery covering of a bird." Most often, it is used to describe the feathers of a fully-grown adult bird. Plumage is not just one feather, but used to describe all of a birds feathers.
The word plumage refers both to the layer of feathers covering a bird, and also the color, pattern, and arrangement of the feathers. The pattern and colours of plumage are different on penguins than on other bird species. Plumage differences are studied by ornithologists and birdwatchers to distinguish between species of birds and gather other specific information.