I would think there would be an inside courtyard, or something similar. They can't live off grasses and roots forever, they're going to have to bring some sort of animal breeding operation in. Rabbits would be okay if they could catch enough wild ones and tame them down without giving them heart attacks to get them to breed because that can be done indoors in a few cells no problem. Chickens as well, if they could find any that are alive. The other issue is that rabbit meat is a little too lean to live off of. They're going to have to find something with more fat on it if they want to stay healthy. Canned food is going to run out. Powdered food is going to run out. They're going to have to figure out how to plant and harvest food without the fear of sabotage from the Governor and his ilk also.