Raising small livestock to help with food sources. I like that they have covered a few different ones in the article. There are chickens and rabbits but they also mention bees which would supply honey as a food but also wax for other things like candles, and quail and fish . These are all pretty much small enough to have in a backyard. This is the way a lot of homesteaders had meat in the diets in the old days. Homesteading families had to raise meat if they wanted to eat any. Nice info from How To Survive It.