A 4-week-old filly is thriving under rehabilitative care after becoming the lone survivor of a massive drought-related horse die-off in Arizona.

Earlier this month, the remains of 200 horses were found mired in mud, dead of thirst around a stock pond in Gray Mountain, Arizona. As volunteers worked to clear the carcasses they discovered a then-2-week-old filly, now named Grace, alive and nestled near her mother.

“She was in critical condition—extremely dehydrated and malnourished when we found her,” said Michelle Ryan, executive director of the Coconino Humane Association, in Flagstaff, Arizona. “We weren’t sure she would make it.”

Grace was transferred to the Aspen Veterinary Clinic, also in Flagstaff, where veterinarians administered fluids to head off kidney failure and treat her hypoglycemia. Once she was stabilized, veterinarians attempted to bottle-feed the filly