No-Guns,
I lived on a 43 acre farm for 14 years. I believe that perhaps you would need to change your learned mind-set about livestock.
FORGET cattle and hogs. Since you already raise them, you know how much trouble and expense they are. And, how much BONE you are paying to grow in these animals.
Goats and rabbits are much much easier to raise, reproduce and grow much faster, can eat just about anything green, can be raised in a much much smaller space, put on weight at a much lower food to weight ratio, and would supply ALL of the meat, milk and cheese that you would ever need. Since they are smaller than cattle and hogs, and grow much faster, they would be easier to trade off on a routine basis.
Unlike cattle, a small herd of goats will actually follow you around wherever you walk. You only need one or two billy goats to keep the herd replenished, so the young kids that are male, you just slaughter before they get to be 6 months old. You keep, or trade, the nanny goats. Just think about how totally desolate the Middle East is: barren, rocky, little grass, little water. And yet, for tens of thousands of years, large numbers of people have lived there (and continue to live there) by just having small herds of goats. The same is true of the mountains in Greece. The land is as desolate as the moon-scape, and yet goats simply thrive.
Rabbits do very well in small cages, AND, their dropping pellets are probably the best fertilizer you will every find! Round, dry, easy to shovel and spread, relatively low in smell. You would spread this evenly in your garden, rake it in lightly, and then watch how quickly all of your vegetables will grow!
With goats and rabbits for meat, you could then keep your chickens strictly for eggs, and sell off the young roosters. (But, where in the world are you going to find chicken feed to feed them?? Even scratch corn? Are you gonna try to grow corn? It would be hard to raise enough. And, even scratch corn would perhaps be better used for making pourage, than feeding chickens.) Maybe you could keep a few chickens alive by letting them free-range during the day, and eat insects?
Perhaps you should buy a few rabbits and milk goats now, just to get the hang of it, and see if you like it. Goat meat is very good, tender, and tastes like mild venison. Throughout Greece, goat-soup is sold everywhere, and is made by cooking a goat shoulder in a pot with some vegetables.
Just my thoughts, based on actual experience. :-)
Regards,
Mannyrock