In just two days, a herd of 100 sheep ate through nearly half of the waist-high weeds in an acre lot at Hartsfield International Airport in Atlanta.

An airport spokesperson says they like the results so far, but need to compare the costs to other weed control measures.

A private donor paid for the airport to test the sheep.

Chicago is also taking bids to hire a sheep crew at O'Hare Airport.

Seattle tried using sheep for a year, but says it had to build too many cages to protect the plants it wanted to keep. Atlanta officials say it will take several months to crunch the numbers and make a final decision.

(KUSA-TV © 2012 Multimedia Holdings Corporation)