What gender are these Muscovy Ducklings?

[puddlestheduck]

I've already tried asking on the Duck thread with barely any feedback, so I'll try posting on here instead. My 4 and 1/2 week old Muscovies are beginning to show their caruncling and have a couple adult feathers. They are only trilling at this point. One of them, the yellower one, has slightly bigger feet. Here are some pictures:

So, any guesses to their genders? I was thinking they were both drakes.

 

[oldhenlikesdogs]

If one isn't bigger than the other than they are probably the same sex. You might have to wait another few weeks to be sure. The one in front looks male, but I would wait.