PETA'S Air Angels drone

KANSAS CITY, Mo. – Drones are doing in the air what animal welfare advocates are doing on the ground — capturing video of livestock operations. The latest subject was a North Carolina swine operation run by Murphy-Brown, a unit of Smithfield, Virginia-based Smithfield Foods, Inc.

In the video, film maker Mark Devries says he has been planning the project since 2012. Footage includes aerial views of a lagoon; interviews with a former hog farmer, a resident who lives near the swine farm and an epidemiologist. Also appearing in Devries's video are clips taken by People for the Ethical Treatment of Animals and The Humane Society of the United States.

The use of drones to film large animal agriculture operations isn't new, but animal welfare advocates opposed to so-called "ag-gag" laws are using drones in an effort to circumvent those laws.

At least seven states have passed laws — while many other states have introduced bills — criminalizing covert filming of agriculture operations. North Carolina introduced an employment fraud bill in 2013, but the state's legislature failed to pass the legislation in 2014. The bill would have prohibited taking aerial photos of swine farms and identifying their locations.

In April 2013, PETA announced the organization would be using drones to follow hunters. The group also began selling its drones through an online catalog.

Will Potter, a Washington, DC-based independent journalist, launched a Kickstarter campaign that raised $75,000 over five days in July. Potter said at the time he planned to focus on states debating laws protecting large-scale agriculture operations, and that he would publish his work in a short documentary and an e-book.