Rainbow Over the Rockies (1947)

Driving a herd of cattle to market, Jimmy finds the trail has been fenced off by an old friend of his. While the two sides try to settle the matter peaceably, a man from each outfit get together to try and start a range war between them figuring they will end up with the cattle. When cattle are rustled, Jimmy finds the clue, horses with shoes that make tracks that look like cattle.

Unfortunately the movie Rainbow Over the Rockies is not yet available on HBO Max.