When Ahern arrived at the scene, she, like the couple, believed the animal had passed away. "She didn't move, even when I was standing right next to her," says Ahern.
Another leg twitch proved her wrong.
"If it hadn't been for the urgency of the situation, I would have burst into tears at the pitiful sight of her," Ahern says. "Surely she was one step away from death. But the sheep hadn't given up and neither would we."
The sheep - named Posy by Ahern - was placed in a stretcher and carried to the sanctuary's rescue vehicle. When the rescue team offered Posy some hay on the drive back, Posy moved her head to have a nibble. "At that moment, we knew we were in with a chance," says Ahern.
Back at the sanctuary, Posy received urgent medical attention. The rescue team realized she had flystrike, a disease caused by blowflies laying eggs on a sheep's skin. When the eggs hatch into larvae, they feed on the sheep's tissue, causing inflammation, general systemic toxemia and, in the worst cases, death. Ahern could see that Posy had been treated for flystrike, but she hadn't been kept confined or monitored for blood poisoning.