You know, someone posted earlier about just doing a smaller "run" type of fenced area. Why not? When I owned the daycare we started out with a small fenced playground. (I'm a big one for doing a little bit over time
)Then as the center grew, and funds increased we had them come out and enlarge the play space. They reused the fence that was there so it was less expensive than buying all new. So you could start out with a small, completely enclosed run, say 8' by 16' or something like that. That would be enough. My guys love to run around the yard here, and I know what you mean about needing to run around to poo (that's Bernie) but on vacation, we rented a cottage with a tiny little fenced yard (it was about 10' from the back of the house/porch to the fence). They adapted just fine.
Just another thought.