Megan Kibby, 33, said she never expected to become a grandmother at such young age. But when Tassi, the goat she raised with her business partner, Jason Lewis, gave birth to twins in the midst of a goat yoga session in Suwanee, Ga., on Sunday afternoon, she was delighted.

Ms. Kibby and Mr. Lewis run Red Wagon Goats, a goat yoga business based in Stone Mountain, Ga. (Ms. Kibby teaches the yoga.) They knew that Tassi was going to give birth soon. Another of their goats, Emmylou, had given birth to twins the previous day and, as Ms. Kibby put it, “when one of them goes they all go.”

They did not think it would happen in the middle of a class.

Red Wagon Goats was holding a goat yoga fund-raising event at one of city’s parks on Sunday, when Tassi — named for the Tassili n’Ajjer site in Algeria — began to paw the ground, looking for a place to nest. Mr. Lewis picked her up, intending to take her to a trailer where she could give birth more privately, when she began to deliver.

“She’s having this baby right here,” he said. (Several days later, the story of the birth was featured in The Atlanta Journal-Constitution.)