Re: @Lord of Cheese (was: Whatever.)
Been there. Done that. My mother keeps some hens for eggs, and she even raised a couple of pigs for their meat a few years ago. (Bloody hard work and, to be brutally frank, not worth the energy and resources. There's a reason why phrases like "economies of scale" exist.)
Mechanised farming is a damned sight easier and more efficient than doing it all the hard way, with oxen, carts, and wooden ploughs.
Also, the population densities around here are much, much higher than in the US; there are parts of the US where you won't see a soul for 300 miles. Ditto in Australia. In the UK, 300 miles is the distance from London to Newcastle-upon-Tyne, so good luck trying to find enough acreage for every single human being in England to become self-sufficient, 'cos it's just not going to happen. The last time the developed nations in the Old World were all completely self-sufficient, the global population was well under a billion.
Most communities, even in the medieval period, would trade with others in order to improve their local staple diets. Livestock would be driven as much as 20 miles in a single day to reach a good market. Money wouldn't have been invented if trade didn't happen.
If you have to barter or trade with others, you are not fully self-sufficient. That requires doing it all yourself. If you have to trust in others to help you meet your lifestyle needs, that's not self-sufficiency. That's just "farming".