I'm really interested in learning more about this. Does he have a website? I've sat down and run some numbers before and it definitely seems feasible, but that's just back-of-the-napkin estimation. I grew up on a farm, but of course we were fully mechanized.
Case in point, I have a former high school friend who runs a farm that’s about 50 acres as his primary business - without major machinery. They have quads and pickup trucks, but most applications where one would use a tractor are now done with animal power.
The result? It’s actually cheaper to operate as grass is cheaper than diesel. He’s not getting rich, but makes as decent living.