That's not really true. The energy used in the cultivation of their feed usually has the highest carbon footprint of the whole equation. "Grass-fed" and similar

That's not really true. The energy used in the cultivation of their feed usually has the highest carbon footprint of the whole equation. "Grass-fed" and similar approaches don't scale up to the demand of meat. They require more land and more labor, all of which increases prices and increases competition for labor and arable land.