Anne O'Connor, who runs a farm with her husband Gunnar, said an earlier check showed the sheep was carrying two lambs, but she suspected there were more because it was unusually large and gave birth slightly earlier. When the lambing began, the number of lambs kept increasing.
"I was a bit suspicious, given how big she was and that she lambed a little early, that she might have more than two. Six is great, but it's definitely more than enough," O'Connor said.
Sources differ in their estimates of how rare such cases are. O'Connor says it happens about once in 1,000 cases, while some agricultural websites estimate it occurs once in a million or even less frequently.
She contacted the Vermont Sheep & Goat Association about it, where they found only one other similar case.
Kristen Judkins of Gilead Fiber Farm, who had a sheep with six lambs, said they take longer to reach full body weight, but most turn out just fine.
"You have to monitor them during the first few weeks to make sure they're eating enough," she said.
The lambs, which are partly Finnsheep breed, have been given Finnish names for the numbers one through six. Their mother is named Teemu, after Finnish hockey player and Hall of Famer Teemu Selanne. The O'Connors plan to keep the four female lambs, while finding a new home for the two males. All animals are doing well.
The farm raises sheep for wool, as well as herbs and berries. It is entering its fifth summer season of sheep farming, and the flock now has 21 sheep, including two other recent additions. Five more sheep are currently pregnant, and Teemu will likely have offspring again after a break.