There is nowhere near enough pasture in the world left for all the meat animals in factory farms to graze freely.
Not that it would make any difference. Free-range animals emit much the same amount of methane as factory-farmed ones do.
More, they consume more of another dwindling resource - land.
If every food animal were free range, we would have to turn a majority of the remaining undeveloped areas in the world into pasture. This kills the planet.
Take a look at this image, which shows all mammal life on Earth.
See those two dozen green squares? Those are all the wild mammals left. Everything else is either us, or our food animals.
In fact, that cartoon is almost seven years old, so since it was made, one green square has been erased and part of another, and two or three grey squares created.
Two hundred years ago, that image was almost entirely green. A hundred years ago, that image was over 50% green.
In my lifetime alone, humans have killed over half the wild mammals (and half the flying insects, half the amphibians, half the sea creatures of any description that are bigger than your two fists put together, etc).
If all those grey squares representing food animals were released over the few remaining green squares, as you propose, what do you think would happen to those green squares? — which represent all the world’s wild mammals, don’t forget.
I do not believe that a compassionate person can really look at that image, see how we have wiped out almost all wild animals with our meat animals, and still argue for meat in any capacity.
