The Marshfield Food Pantry has outgrown its 700-square-foot location at the First Congregational Church and is looking for a new space, according to director James Hewitt. In a recent letter to the Board of Selectmen, Hewitt said that with more space, the pantry could save money by buying in bulk and taking full advantage of the resources of food banks in Boston and Plymouth. The pantry serves more than 250 families a month, up 20 percent from 2010, he said. In a meeting with selectmen this month, pantry representatives told the board they would like to use the old Boys and Girls Club, which the town owns. Selectman Matt McDonough said various groups have expressed an interest in the space.