If you can do this in your home yard, this is a good start on being prepped.
http://survivalathome.com/backyard-meat-animals/While not all of these animals are suitable for all climates, you should be able to pick one or more which will work in your area.
I've raised chickens and rabbits, in Washington State (think rain and relatively overcast skies). They were both a near break-even food source in terms of what their food cost versus the cost of purchase for the same eggs and meat.
The plus side was that Rabbit meat was selling for more than their food cost and fresh eggs were in demand when I had surplus, which generally covered chicken food cost, and of course I was getting fresh eggs and meats for my own consumption.
Upkeep was fairly minimal, daily feed and water, cleaning the pens (both give great fertilizer) and slaughter every few months. I did exchange roosters with a neighbor about once a year, which let me keep the gene pool a little more random. The rabbits were so prolific (it's a rabbit thing) that I could sell my live bucks for more than the cost of two does.
I would also look at ducks, as noted in the reader comments to the article. I had a stream and pond, but no effective way to fence it. Keep this in mind with ducks, they will leave if allowed. Chickens will escape but not wander far and they return at night. Predators are a problem (think local dog packs, coyotes, weasel and muskrats).