I have three cats. Only one ever showed interest in outside, so we got him a harness and leash. He loves it, the best treat in the world. Now we live somewhere with a fenced in back yard, so we let him out with no leash on supervised play times, and one of his sisters has shown an interest so she comes with us into the yard. When we can't be with them as supervision, they stay inside. Not so different from a small child.

We also play with them all daily and are currently building an elaborate climbing wall to keep them entertained better during the sweltering heat of summer. At no occasion do they need the opportunity to murder in order to be happy.