CHICAGO (CBS) — The city of Chicago is set to employ a herd of goats to clear vegetation at O’Hare International Airport.

WBBM Newsradio’s Mike Krauser reports the Chicago Department of Aviation has awarded a contract for sustainable grazing services to Chicago-based Central Commissary Holdings, LLC.

The Aviation Department said the pilot program provides a way to cut costs and make O’Hare more sustainable and eco-friendly; by providing an alternative to toxic herbicides, and reducing use of fuel for lawnmowers and other landscaping tools.

The herd of 25 goats, now on a farm in Barrington Hills, is expected to start work in about a month, after enough foliage has grown at four sites where the goats will graze. It’s expected they’ll clear about 250 square feet of vegetation per day.

The city said the goats will be especially helpful in rocky and hilly areas around the airport that are hard to reach with lawnmowers.

The goats will be supervised by a herder while they’re grazing during the week, and housed overnight in a nearby transport trailer.

The contract runs through the end of next year, and calls for a maximum payment of $100,000 to Central Commissary Holdings.