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08/29/2014 04:37 pm ET Updated Aug 29, 2014

Airport's Incredibly Cute Lawn-Trimmers Are Back On The Job

Guess who's baaa-ck?

The Chicago Department of Aviation announced Thursday that it has once again "hired" several dozen goats, sheep, burros and llamas to graze on the grounds of O'Hare International Airport.

The airport first introduced the low-tech, eco-friendly initiative in 2013. The animals, all obtained from a suburban rescue shelter, focus on areas of the grounds that are typically difficult to maintain using traditional equipment.

The furry crew of almost 40 has been back on the clock since this July and was responsible for eating up five acres of dense, overgrown vegetation between July and November last year. The animals' diet even includes poison ivy, which is safe for them to consume and "they seem to find delicious," according to the city.

Airport officials told WTTW's "Chicago Tonight" the animals -- which spend their days simply eating around the clock -- are probably the airport's happiest employees.

Eating wasn't the only thing going on last year among the all-you-can-eat crew. A male lamb was born there last August, the Chicago Sun-Times reported.

At least three other airports -- in San Francisco, Seattle and Atlanta -- also rely on four-legged grazers for weed control.

Here are the animals on the job last year:

ohare goats

(MIRA OBERMAN/AFP/Getty Images)

ohare

(AP Photo/Jason Keyser)

ohare goats

(AP Photo/Jason Keyser)

ohare goats

(MIRA OBERMAN/AFP/Getty Images)

ohare goats

(MIRA OBERMAN/AFP/Getty Images)

ohare goats

(Photo by Scott Olson/Getty Images)

ohare goats

(MIRA OBERMAN/AFP/Getty Images)

ohare goats

(Photo by Scott Olson/Getty Images)

ohare goats

(Photo by Scott Olson/Getty Images)

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