Of the total area that is used by humans (Agriculture, Urban and Built-up Land),
- urban and built-up land is 1m km²,
- agriculture is 48m km²,
so agriculture is 48 of 49 millions km² used, that’s 98%. The remaining 2% are all streets and housing and other infrastructure together.
At that point we don’t need to farm animals.
Best thing to do at that point would be to outlaw breeding of new farm animals, send the remaining ones to sanctuaries, and let them live the rest of their lives out on their own terms. Might need to sterilize as well.
All of this would aim to restore natural populations of cows, pigs, chickens, goats, sheep, etc. in the world to native levels. And if those animals aren’t native, then imo there is no reason to help sustain them. Release to the wild at some point and let nature take it’s course. Of course, this also means restoring natural predators to ecosystems like wolves, which would help keep populations in check.
Those species that are native, however, but are declining and on the brink of extinction: those we should focus on for conservation and regeneration.
It’s a tough balance, but it can be done ethically