Mark Duffy operates Great Brook Farm in Carlisle, Massachusetts. Alongside his family, he milks 120 cows using a robotic-milking system. Milk from the farm is made into cheese and other dairy products by farmer-owned Cabot Creamery Cooperative/Agri-Mark. Duffy is a director on the board of New England Dairy and Agri-Mark . Agri-Mark markets more than 300 million gallons of milk each year for more than 850 dairy-farm families in New England and New York.