NUNN, Colo. — As the sun peeks over the fields of organic grain in this grassy patch of the state, some mornings, a dark dot appears in the sky as well, and a loud buzz slices through the pastoral scene.

It is a drone, and its pilot is a farmer named Jean Hediger, one of a growing number of American agrarians who have taken to using unmanned aircraft — better known for their use in war-torn lands far from the wheat fields of eastern Colorado — to gather information about the health of their crops.

In doing so, these farmers are breaking the law. It is illegal to fly drones for commercial purposes without permission from federal authorities, and those who do so risk penalties in the thousands of dollars. But the technology holds such promise that many farmers are using it anyway, dotting the country’s rural skies with whirring devices saddled with tiny video cameras.

“This has really become a big deal in ag,” said Ms. Hediger, who is in her early 60s.

“Our intent is pure,” she added. “Without being able to fly drones over our fields, they are asking us to remain in the dark ages.”