The tab was $2,300, paid out of a larger Peco Green Region grant administered by the Natural Lands Trust.
A delighted Jeanette MacNeille, the Borough Council president, declared the goats "economical, as well as environmentally sound."
The animals did not run on fossil fuels, and they left fertilizer behind. They also took care of weeds most volunteers wouldn't touch: poison ivy, which might as well be called goat candy.
And how's this for model employees: They didn't need health insurance (although Knox's goats have liability insurance). They never ask for days off. The bigger and baaaadder the job, the better.
Now, with society's fervor for sustainability, goats are gaining cachet. Plus some colorful monikers: walking lawn mowers, graze anatomy, free-range landscapers.
Last June, New York City officials turned 20 goats loose in a phragmites-ridden Staten Island wetlands they plan to turn into a park.
In September, Chicago officials issued a request for bids for a herd of grazers to clear overgrown areas of O'Hare International Airport. One requirement: not being rattled by the roar of airplanes.
In Southern California, where brush-fed wildfires are a threat, goats are a frequent sight in municipalities trying to clear the tinder.
They have been deployed at Google's Northern California headquarters and at the historic Vanderbilt Mansion in Hyde Park, N.Y.
In this region, modern use of rental goats dates at least to 2009, when Yvonne Post of Atglen took Rodin and Wyeth - Angoras who also provide her with mohair - to Bartram's Gardens, where they munched on thistle, mugwort, and vetch.
Next, they taste-tested garlic mustard at Longwood Gardens. They didn't like it, but they nibbled on some invasive bamboo, which led to a stint in Fairmount Park.
Last year, a bigger crew that included Caravaggio and Kandinsky was tested by Friends of the Wissahickon.
Botanists evaluated the plants growing at different plots, and the goats were pitted against humans, an herbicide, and a control plot.
The contest, which has expanded to Andorra, has not yet been decided, although Post said that when the target species is poison ivy, the goats reign supreme.
Friends' executive director Maura McCarthy pronounced them "adorable."
Then again, besides weeds, they also exhibited a taste for valued native species.
"They even ate spicebush," said one of the judges, Janet Ebert, a consulting botanist for Bowman's Hill Wildflower Preserve in Bucks County. "Not even deer will eat spicebush . . . unless there's nothing else to eat."
So in mixed plots, humans remain the clear choice, McCarthy said. "You really can't beat them when it calls for judgment."
Meanwhile, Upper Merion plans to let Post's Angoras loose on a 10-acre section of Bob White Park, where mile-a-minute vine and multiflora rose are overrunning the place, even killing trees.
Officials had tried using goats the township owned previously, but "they are spoiled" - meaning too domesticated to go for the weedy stuff - said Dan Russell, the township's director of parks and recreation.
"We really want to be on the cutting edge here and see if this can be an effective solution," he said.
Eco-Goats, the firm that Millbourne used, runs 70 to 75 goats, split into two to three crews. Knox started the business as an experiment four years ago, and "it was so wildly successful, it took over my summers."
He is part of an online consortium, www.Rent-A-Goat.com, where weed-weary land managers can find a herd.
Other places have goats on staff.
Folks at the Lanchester Landfill in Honeybrook have been trying the combo approach - sheep for grass, goats for the weeds.
The animals did more than clear vegetation. They were all but a tourist attraction. And, said Dawn Nichols, who has the unusual title of operations wildlife livestock manager, "they've been very reproductive." The initial 20 sheep in 1999 eventually became 120, and last month, Nichols shipped half of them out.
The Natural Lands Trust opted for just two goats, neutered males named Seamus and Duffy, who have been wolfing down invasives at the Crow's Nest Preserve in northern Chester County.
The rest of the staff has found that the goats are an educational tool.
"They are, quite literally, a warm and fuzzy way to talk about invasive plants and our approach in dealing with them," said trust spokeswoman Kirsten Werner.
Not everyone is gaga over goats. Folks at the Wissahickon Valley Watershed Association, who have waged a pitched five-year battle with knotweed, decided on yanking and chemicals instead.
"Everybody loves the goats, but no one wants to take them home for the weekend," said Bob Adams, director of stewardship.
A goat lover in Western Pennsylvania found himself butting heads with Jeannette city officials after they passed an ordinance prohibiting goats and other livestock.
Vitriol and fines ensued, never mind the goat's 2,500-plus "friends" on Facebook.
The goats' owner, Frank Trigona, marched them in the Halloween parade and named them after city officials, but finally sent his animals to a more traditional weed-clearing locale for a goat: a farm.
Contact Sandy Bauers at 215-854-5147, email@example.com, or follow on Twitter @sbauers. Read her blog, GreenSpace, at www.philly.com/greenspace.