I put my ducks in their enclosed houses late at night so they'll be safe & so I can easily find their eggs in the morning. When I didn't do this they'd lay their eggs in the bottom of their pool!
I started with 5 Khakis in one house, then got 4 more & added another house, and now 2 Pekins in their own little house. Three duck houses all in a row. And the pen next to it for the 2 Embden geese. We have to round them up at night to make them go into their houses, but it's funny to watch them all turn into just the right door for them and wait to be latched in.