No i havent read the book before
Mumble is an emperor penguin (i believe) that has a disorder that affects the shedding of his Down (the soft feathers that the young usually have)
Completely unrelated, but that is a great sentence, I want that painted as a quote on my wall.
Also, the punctiation seems right to me. But you might be able to use a ";" instead of a comma, im gonna check that real quick.