An animal welfare group is calling a horse rescue in Shelburne "the worst case of abuse and neglect we have ever seen."

Clarendon-based Spring Hill Horse Rescue issued a press release Thursday saying it was called to a property in Chittenden County last Tuesday, January 15, to help three horses in dire straits. The group said it found two mares and a stallion that had been locked in small, dark stalls for several years.

"They were standing on several feet of built up manure — and were running out of room to stand upright," Spring Hill's statement said. "The bones, hair and hooves of their former herd mates surrounded them. These were the three survivors."

Chittenden County State's Attorney T.J. Donovan said Thursday that his office has opened a criminal investigation into the alleged abuse, and confirmed it took place in Shelburne. Neither he nor Spring Hill Horse Rescue would name the property owner.

Donovan said his office was consulted about the rescue last week but that no search warrant was issued. He said the horses were removed from the property.

"It appears the owner consented to hand them over," Donovan said. "They were not seized."

Animal welfare groups say they've seen a disturbing number of horse abuse and neglect cases lately, and have complained that Vermont law enforcement do not treat animal cruelty cases seriously.

When Spring Hill volunteers found the stallion (pictured), named Willie, his teeth were rotted and he was covered in lice, the press release said. "His hooves are the worst cast of abuse and neglect we have ever seen," the group said. "He had trouble walking; it took six people to help lift him onto the trailer."

Spring Hill personnel removed 24 inches of overgrown hoof (pictured at top) from Willie, which they later found infested with maggots. "Willie is almost blind, most likely due to living the dark for years," the group said.

The mares, named Dolly and Lolly, were "utterly terrified as they have had little contact with humans," Spring Hill Horse Rescue said in its press release. Their hooves were also overgrown (Lolly's hooves are pictured below) and both mares are showing signs of limited vision.

Donovan said he did not have further information on the case, as he had not seen paperwork from Shelburne police. Deborah Loring of Spring Hill Horse Rescue said she could not discuss details of the case beyond what's in the press release, pending a possible criminal investigation.

Photos provided by Spring Hill Horse Rescue