In June 2013, Commonwealth Dairy completed a $12-million expansion of its $28.5-million plant to support a new product line. And on Monday, Thomas Moffitt, Commonwealth Dairy’s president, returned from Casa Grande, Ariz., where it and its partner, Ehrmann AG, just opened a new facility. The state-of-the art yogurt manufacturing facility in Arizona was built by the same company that built Commonwealth’s factory in Brattleboro, said Moffitt, but it’s twice the size. Currently it employs 110 people and Moffitt said in two years they hope to have 250 employees.