The protests around Australia have also raised questions about vigilante action and its consequences. One goat farm says it was forced to close by sustained bullying.

“Our staff and customers have been subjected to nearly four months of constant harassment, vile statements and threats from the abusive vegan activists,” the Gippy Goat Cafe said in a Facebook post on Sunday . “The courts have proven to be ineffectual, the enforcement agencies declined to prosecute to the full extent, so, to the thieves, trespassers and activists; you have won.”

Farmers and government officials say they are concerned about violence.

In February, activists circulated footage of a dairy farmer in the state of Western Australia firing his shotgun into the air while they were in a car filming his property, although the gun is pointed away from the car and the farmer has said he did not know they were there.

Brendan Farrell, a cattle farmer who runs a group that donates hay to farmers affected by drought, said he worried that if the trespassing continued, someone might get killed.

“They’re going to go on the wrong person’s property somewhere in this country where someone has had a gutful,” he said. “The writing is on the wall.”

Mr. Delforce said he and other activists were willing to endure the risks to expose what he says is an opaque and inhumane system that he believes would sicken Australian consumers.

“Most Australians are opposed to animal cruelty,” he said.

In recent years, the vegan movement has also gained traction in Australia because of increased awareness of animal agriculture’s contribution to greenhouse gas emissions, which cause climate change. Approximately 11 percent of Australian adults eat a mostly or completely vegetarian diet, a proportion that has slowly but steadily risen, according to a 2016 study.