It started with neighbors' complaints.

A new resident planned to board horses at her farm in Newlin Township, a rural swath of Chester County where horse farms and boarding facilities abound. Worried that the operation could transform sleepy lanes near their homes into bustling roadways, neighbors sued.

So, Newlin officials amended the township's zoning ordinance a year ago to restrict activities of horse businesses, including limiting the number of horses allowed per acre, a step that outraged another constituency.

Now, the little rift in a town of 12 square miles and 1,300 residents has grown, especially in the equestrian community, which fears any restriction might set a precedent.

Relying on a state law passed a decade ago to force municipalities to comply with state statutes when they attempt to regulate agriculture, residents statewide have filed dozens of complaints over such local laws.

The state Attorney General's Office has found legal flaws in 52 of the 106 ordinances it has reviewed and sued townships that failed to fix them. The same option is being weighed in Newlin Township.

Kristin Camp, a lawyer for the township, said the supervisors tried to balance residents' competing interests, but knew no solution would please everybody.

"They were damned if they did and damned if they didn't," she said.

Horses are major revenue drivers in Chester County, farming groups say, and the industry has a symbiotic relationship with the rest of agriculture in the region, such as hay and straw producers and the mushroom industry it supports with manure. Some horse farmers in Newlin say the ordinance is depriving them of income.

"It's unfortunate when neighbors' disputes are handled by putting a lot of pressure on someone's livelihood," said Ann Swinker, a horse specialist and associate professor of equine science at Pennsylvania State University.

Officials from Newlin and the Attorney General's Office plan to meet in early January to discuss the next steps to avoid a lawsuit.

The state wants Newlin to amend or rescind the ordinance.

"Pennsylvania law provides state agencies with strong and broad regulatory and enforcement power over all agricultural operations and prohibits inconsistent regulation by municipalities," Susan Bucknam, a senior deputy attorney general, wrote in a letter to the township.

Township officials maintain their statute is legal.

Steven Siepser, an eye surgeon, and his wife, Susannah Small, told the Attorney General's Office about Newlin's ordinance last year. Their Laureleye Farm includes a sheep, goats, donkeys, and chickens on more than 70 acres.

But the more than 30 horses and ponies they own or board at the farm are their most lucrative animals, which is true for many of their neighbors on farms, Small said.

"Without the horses, most people who own these properties wouldn't be able to keep their properties," she said.

Small, a third-generation equestrian who runs the farm, said she can no longer give riding lessons there because of the ordinance, which she says costs her about $1,200 per month in income.

The ordinance includes a mandate that horse farmers have three acres for their first horse and two more for every additional horse, which equine specialists say is excessive and beyond state regulations.

"The amendment was designed to allow the boarding of horses and other equestrian activities with reasonable regulations that are aimed at protecting neighboring property owners and preserving environmentally sensitive natural resources," the supervisors said in a statement.

Pam Brumfield estimates she lost $3,000 in revenue over two months when the ordinance forced her to keep five of the 20 or so horses she cares for at three neighboring farms.

"The money was less of issue than the stress involved in taking care of these animals in a situation that did not need to occur," said Brumfield, who has worked at Maresfield Farm for nearly 30 years.

Ed Brown, a commercial mortgage banker who owns Maresfield Farm, found a temporary solution when neighbors let him lease 10 acres of their land for $1, which lets the horse operation stay within the per-acre horse limits.

But that spawned another legal battle with a few nearby residents, who said they were concerned about water runoff from the farm.

Brown said he had paid thousands of dollars in legal fees to keep Brumfield's horse operation going.

Now, like many others, he is waiting for a resolution.

"I think the state will not let this stand," he said.

610-313-8207@MichaelleBond