One of the survivors is tended to.
The Louisiana Horse Rescue Association (LHRA) now has 45 of the horses in its care.
It said it was contacted by the Sabine Parish Humane Society on January 6 asking if it could help in removing and housing horses it planned to seize from the property.
The LHRA agreed to take the horses and organize removal over the weekend of January 7-8.
The Louisiana Veterinary School's Equine Response Team, including a vet and two vet technicians, met members of the groups onsite on the Saturday.
"We were not prepared for what we found," the LHRA said on its website.
"On arrival, we were taken to a barn at the rear of the approximately 250 acre farm.
"The barn housed a group of two-year-old colts as well as a handful of horses of racing age. The horses were in deplorable condition.
"They were severely underweight, lethargic, and stood in stalls full of urine and manure that had not been cleaned in weeks.
"Their manes and forelocks were full of burs. One had a wound on his forehead and old, dried blood running down his face. Two of the horses showed mild colic signs and one had significant swelling along his abdomen and into his scrotum."
Those involved found three horse carcasses in the woods short distance away.
In the broodmare pasture, horses were found that were said to be too weak to get up, as well as a gelding with severe colic, who was later euthanized.
Carcasses of horses that had recently died and aborted foetuses were also located. The field was scattered with bones from what they believed were horses, goats, and dogs.
Later reports suggested the remains of about 25 horses were located.
A youngster is urged to load on a trailer.
One member of the LHRA headed into town to buy tarpaulins to cover the dead animals.
"I drove to town to get as many tarps as I could find. I will never forget walking through that pasture placing tarps over those majestic beasts. I had to lift their legs and heads to secure the tarps from flying off.
"It was a gorgeous day, uncommon for this time of year, and all around us were nature's gifts - birds, geese, trees rustling in the light breeze.
It was peaceful out there, and I covered the horses quietly. I recall thinking what a stark contradiction it was - such hideous abuse in such a gorgeous setting.
"Most of the day was spent photographing and examining each broodmare to determine which were in foal, what their immediate needs were and to record their markings and tatoo numbers to help identify them later.
"It was mid-afternoon when we drove the truck and LSU minivan down into the last pasture.
"Here we found an oddly mixed herd of older ex-racehorses, two-year-old fillies, and a group of yearlings. Three of the yearlings were literally shooting water out of their backsides. I've never seen such terrible diarrhoea."
In all, seven horses were removed on the Saturday.
A bigger team was involved the next day in documenting and assessing the horses and removing most of them.
Many bones were found on the property.
The 13 horses were removed from the property on January 10.
Sunday was described as a whirlwind of paperwork, veterinary care, phonecalls, emails and meetings. Two of the yearlings died, despite around the clock care. All other horses are reported stable so far.
The group hopes the healthier of the horses could be available for adoption in as little as three weeks - two weeks to satisfy a Louisiana statute allowing the owner to post bond and another week to work through ownership issues.
The LHRA says the care of the animals is costing $US450 a day and it appealed for help with the costs.