Most of our meat in the US comes from factory farms.

> 70.4 percent of cows, 98.3 percent of pigs, 99.8 percent of turkeys, 98.2 percent of egg-laying hens, and over 99.9 percent of chickens raised for meat come from factory farms.

https://www.livekindly.co/99-animal-products-factory-farms/

This said, the range that beef cattle occasionally graze could be reclaimed, but not necessarily for legume production.

Legumes: https://gilmour.com/planting-zones-hardiness-map

Beef: https://www.sciencedirect.com/topics/agricultural-and-biolog...

There is overlap, but no where close to 100%.