I would say about 5 acres would be enough, obviously the more the merrier but you need to keep costs down, but the poultry don't need to be penned up as such except for in their coops at night, you can grow a hell of a lot of veg in small areas, you only need a few sheep, a dairy cow and bull (optional) and a few pigs.
The sheep and cattle can field share, and the pigs don't need that much room, although again the more space the better.
If you have a river near by with trout in or a coast near by then you have a supply of fish, and if you have woodlands near by or on your permissions where