Defense....hmmm. Here's the problem. I grew up listening to the old people talk about chickens during the depression. They would have 5 chickens, and when they had to leave the property, a small lot. Someone would come and steal one. And cut the wire open to do it letting all the others out. Setting up your own 'compound' to feed your own will work, only as long as you can keep the roving gangs and masses out. As soon as they discover you have something, they will come and take it. Ever see one chicken try and keep a piece of bread from the other 30?