That's a really big question, I think the simplest way to answer is to say, "(Mostly)Let animals be themselves, kill them quickly". With regard to cows which I

That's a really big question, I think the simplest way to answer is to say, "(Mostly)Let animals be themselves, kill them quickly". With regard to cows which I know the most about that means letting them eat grass and only providing input when necessary to protect the health of the herd from an unexpected insult, e.g. unexpected drought, or to promote the health of the land. Because I've not tried this on a nationwide scale I can't guarantee that it could be done, but based on the thought I've given to it and my own experience I believe the majority of beef production _could_ be done humanely with the caveat that it would likely be unprofitable to do so given our current economic and cultural landscape. I don't think dairy can be done humanely at scale for our current consumer price point.