Ah!. The head does look suspiciously dusty for a Rouen, now that you mention it. I believe you're right! I'd love to see updated photos of this little cutie as he/she grows. :)
What an odd little stinker!! You're sure there's no way a Muscovy had a little fling with her? I know that a white gene will come forward in Khaki Campbells, for example, and produce a yellow duckling, but that definitely looks like a Rouen drake. I must research this! I'd love to hear from...