You might as well kill them now, because trying to turn an indoor cat into an outdoor cat is a death sentence. Their survival skills and natural distrust for everything have been muted by years of domestication. It would be like dropping a suburban housewife into a dangerous slum alone, and telling her that she’s on her own, but you’ll drop off some food a couple times a day so she doesn’t starve.
Uggh!
Our cats used to be indoor cats until 2005 when they both decided they prefer it outside. They have been happy outdoors now full-time for 6 years..