Duck House and Pen Questions

[chickengal7]

I am considering getting ducks sometime in the future. Currently I have a 10x10 fully enclosed pen and a small coop just big enough for my three Speckled Sussex chicken s. I only want 2-3 ducks... could they live in my current pen with my chickens? I know they would need a house of some sort, any ideas?

 

[Amiga]

Many people have mixed flocks. Ducks love water, so a separate section for splashes makes sense.