Keep in mind that I am a rookie and probably don't know what I am talking about.
I brought 4 Toulouse geese home two nights ago. I was told by a bird guy that I could put them in the chicken house while I finished the Goose shed, but that my chickens would likely quit laying for a week or so. I put my first ducks with the chickens a couple weeks ago and those chickens are still laying, but they do not like the ducks one bit, so they will also have their own shed. My geese are presently in our cedar fenced courtyard while I finish their shed.
Hopefully they will all have their own condo by the end of this weekend or early next week. My ducks and geese will share the same yard/run and everything will free roam during the day.
The sheds I am building are small, 4x6 lean-to's, single wall construction. One for the 6 ducks and one for the 4 geese. They aren't too expensive, so if they turn out to be too small, I'll build more and connect them. Materials for two sheds cost me about $350 at Home Depot... total.
So far, when allowed to all be together, the chickens haven't picked on the geese, but they do pick on the ducks. The ducks like the geese, and the geese seem to just tolerate them... a bit of hissing back and forth. The geese haven't bothered the chickens... they seem to just ignore them.
Good luck.....
Dan