My husband's grandfather has a huge orchard (apples, pears, cherries) in Wenatchee and we got the apple bins for free...but I see them all of the time for $10 each. They are 4' x 4' and work perfectly.
As for the "no climb" fence...it's horse fence but I wouldn't use it for my horses! It was...
I use this design for my Muscovies, too. The apple bins were $10 each & I used scrap OSB to make the "roofs." I also used some foam sealing stuff (Great Stuff is the brand) to seal the cracks. The geese picked most of it off, though.
Here are some pics!
Future pen for yet another breed...
I use apple bins, turned up-side-down with a sheet of OSB on the top (actually the bottom) and a hole cut in the side. They aren't fancy, but they give them shelter from wind & rain.