A group of wild horse advocates is asking a federal court to prevent the U.S. Forest Service (USFS) from selling horses gathered and removed from Modoc National Forest, in Northern California.

Earlier this year, the USFS announced a plan to gather about 1,000 wild horses from the Devil’s Garden herd on grounds that the herd had become too large for its range to support. As of Oct. 20, more than 400 horses had been removed during the ongoing. The gathered horses would be sold or adopted out, the USFS said.

But, in a complaint filed in U.S. District Court for Northern California on Oct. 19, the American Wild Horse Campaign (AWHC) and the Animal Legal Defense Fund allege that the agency would sell the horses “without limitation,” possibly allowing them to be sold to buyers who would resell them for slaughter. The complaint said such sales violate a long-standing agency policy.

“The Forest Service’s decision to treat these national treasures like trash by selling them by the truckload into the slaughter pipeline is unconscionable,” said Suzanne Roy, AWHC executive director.

Ken Sandusky, a USFS spokesman, declined to comment on the pending litigation but said the agency has a history of doing its best to place the gathered horses.

“We do our best to make sure these horses have good homes,” he said.

The case is pending.