Here's the duck house I'm building. Its 3' by 5', with a duroc (concrete board) floor. The posts and roof trim are cedar, but everything else is 2 by 4 stock I had laying around.

The roof is on hinges, with a latch on the front, for easier cleaing. Since a solid dog house structure would suffocate the ducks in the Texas heat, I am making the outside walls just half-inch hardware cloth, 24" high. It will go on the outside of those 6 cedar posts, with a gate on the front. I cold winter, I'll screw some plywood over the sides to block the wind.

We took the ducks about 250 feet to the 1-acre tank (pond) today. They really had a good time, but never got more than 5 feet from the shore, mainly diving and pecking away at the vegetation. We wondered how we would get them out, but as we started walking off, they all followed us back to the shop. Now I wonder if they will stay out at the tank at all.