I have chickens and just got ducks. I have 4 three week old Mallards that I just moved into the coop (in their own pen) and they don't seem to mind each other at all. I ordered 10 more ducks that arrived yesterday with 4 roos (ugh) And sent an email to a local who has 4 BSL chicks that she wants to sell. I don't have room to brood the chicks and ducks separate, but the kiddie pool that they are in is plenty big enough for the chicks to stay dry. So far so good, but I have to tell you that the older ducks were extremely wet and messy and they poop everywhere. I got the warnings from people on here about how messy ducks were and I figured, "I've got an infant and 3 yr old, how bad could it be" Well, awful and stinky.....but well worth it. If you are in a warmer climate and can brood them outdoors, you should do that. 3 weeks was enough stink I could handle in the house.