That is a very good question and I appreciate you asking it sincerely. I would say from my research and observations at this point that it is difficult to raise animals completely free range, i.e. not supplementing with grain and legumes, for mostly economic and logistical reasons at this point in time. Also if you think about the massive amount of time and energy behind creating the complex and multinational infrastructure for grain production and distribution, you can see how hard it would be to shift to a perennial agriculture. See Merchants of Grain by Dan Morgan for the incredible story behind all this, which is not well known at all.
Wes Jackson at the Land Institute is working on a perennial wheat which could be a game changer overall — tillage will always be the biggest killer of animal life in agriculture as far as my comprehension understands, and so no-tillage would save many lives.
I think we need to grow the small family farm again, firstly for quality of life for rural folks and the animals that they eat. I want to see happy hogs, cows, chickens, and turkeys in the sun, not in CAFOs — that is really what drives my work.