My wife and I are both hunters/fisherpeople and between our seasonal tags we get to fill our freezers every year with meat to last us almost 9 months. I only eat free range meat when not eating venison and even then red meat twice a week maximum. Most of my protein is from free range eggs.
Before I concern myself with what industrialized farming is doing, I would concern myself more with not breeding more than two kids per household (this is purely my opinion). Less population = fewer resource consumption, period. So my biggest contribution so far is a vasectomy. I think how much I saved this planet in resources by choosing NOT to have kids and although it's not enough, it certainly is more than than a dietary adjustment.