More than 100 horses described by an equine welfare organisation as emaciated have been formally surrendered to two horse rescue groups in the US.
The horses at 3-Strikes Ranch, in Morrill County, Nebraska, were legally surrendered to horse rescue groups Habitat for Horses and Lifesavers Foundation.
The agreement to sign over the animals was co-ordinated by the Morrill County Sheriff's office, which earlier in the week arrested the owner, Jason Meduna, on one count of animal cruelty.
3-Strikes Ranch, according to its website, is a "Mustang outpost ... a habitat to hundreds of mustangs from all over the United States ... a natural environment for wild horses to run on the open prairies of the Sand Hills."
Some of the mustangs captured by the United States Bureau of Land Management that were not adopted after three attempts - called three strikers - were sent to Meduna at 3-Strikes Ranch.
Jerry Finch, of Texas-based Habitat for Horses, had found that Meduna's ranch had pastures devoid of grass with little or no edible grazing.
On Sunday, Finch accompanied a sheriff's deputy in a flyover of the property.
It was then that the bodies of more than 60 dead horses were discovered.
Nearly all of the animals on the ranch were malnourished, their back, ribs and hip bones were very pronounced, the group said.
Two animals were so compromised, it was determined that euthanasia was necessary. Laboratory reports on the cause of death will be returned by Friday of this week.
Finch applauded Meduna's decision to surrender custody of the animals, saying "we can now give these horses the medical treatment they need to get them on their feet again".
The horses were moved initially to the Bridgeport Rodeo Grounds for veterinarians and volunteers to examine and treat each horse as needed.
Finch estimates that more than 30 stallions were in the herds, indicating many of the mares may be pregnant.
According to Jill Starr of Lifesavers Foundation: "The ultimate goal is to place these animals in homes and facilities capable of addressing their needs and where they will have the opportunity to thrive".
Habitat for Horses, in a release, said the Meduna had also been accepting horses from people unable to care for their mustangs, and those in need of special training. A number of private owners who had placed horses with Meduna had already retrieved their animals.
The Bureau of Land Management was at the facility last week and removed one of the three horses for which they currently hold title. The other was reported to be dead.
Habitat for Horses reported that the Meduna said more than 300 animals were living at the ranch in January. "He has attributed the deaths to toxic poisoning, but to date no proof of this has been provided," the group said.
It is understood he made an earlier complaint to police over alleged poisoning of the horses on his property.