A couple weeks ago I got two Pekin ducks (i think) I have no idea what sex they are. One is bigger than the other so I am assuming its just older by one or two weeks. The big one started to get its feathers in about a week ago and they are the normal white color. The smaller one is just starting to gets its feathers but they are brown. Why would its feathers be coming in brown? Should I be worried? Is it a different kind of duck?