To try to deter the Kittens from wanting to escape through the doggy door, we built a catio. It's mounted to the house and gives them a screened room with clear roof for sunbathing, bird watching, etc. Later on, we'll build more and add catwalks in between them, but phase 1 is complete, and they seem to enjoy it! I can't give exact instructions, because it was a general-idea-build-in-place project, due to having an old house. Basically, figure out how to box in the window, build a roof and door, screen it all in, and add shelves, walkways, and perches, planning for any future phases (we put a high shelf above the door as a ledge for a future cat walk).
To try to deter the Kittens from wanting to escape through the doggy door, we built a catio. It's mounted to the house and gives them a screened room with clear roof for sunbathing, bird watching, etc. Later on, we'll build more and add catwalks in between them, but phase 1 is complete, and they seem to enjoy it! I can't give exact instructions, because it was a general-idea-build-in-place project, due to having an old house. Basically, figure out how to box in the window, build a roof and door, screen it all in, and add shelves, walkways, and perches, planning for any future phases (we put a high shelf above the door as a ledge for a future cat walk).