When they arrived, rescuers couldn't believe their eyes.
They found the pony and horse standing on manure that had accumulated nearly 2 feet high. The animals were also so emaciated, they risked death.
"[The] pony and horse have a body index (condition of being overweight) of one in five, the last stage before death by undernutrition," the sanctuary wrote. "It is cachexia, or extreme leanness, that causes muscle wasting, the body literally self-consuming."
The pony weighs just about 154 pounds, "the weight of a big dog." Normally, Shetland ponies weigh about 450 pounds.