Stopping bears from walking through walls?

I attempted to set up a zoo and wrote a plug in that would set up "teleport" points inside cages that i built. If i shoot an animal i can teleport the animal to the point inside the cage using npc.transform.position, then SendNetworkUpdate. This works, but then the bear just runs right through the cage walls. I can delay this by setting npc.state to BaseNPC.State.Sleeping. but eventually it wakes up, walks through the walls and kills the zoo patrons.

I have seen various posts complaining about the fact that animals can walk though walls, and i don't think it's been an issue that's been fixed.

But does any one know of a way to force a particular bear to not ghost through the walls. Maybe add a ridged body to the npc, or something. Or any clue as to how to handle this issue?