Best way is to buy your meat from a local butcher. I've said this before and I know that not everyone is lucky enough to have a butcher nearby, but if you do, then please use him. This way, it supports the small business and you can guarantee where the meat (not just chicken) comes from. I'm happy to pay a bit extra for quality, not just from the animal welfare point of view, but for the sake of knowing what we're eating!! I fully understand, though, that some families are on a tight budget and can't afford it, but really, if more people learned to cook proper meals instead of relying on cheap rubbish and ready - meals from the supermarket, we'd turn things around. It's amazing what you can rustle up from a few basic ingredients - just see Jamie Oliver (although I'm not his greatest fan - he irritates me!!) and "feed your family for a fiver"!
Alternatively, get an allotment & grow your own.