Bob, not sure this will assist you, the time period may work but it is from the New England area. Have you checked out Thomas C. Hubka's book, Big House, Little House, Back House, Barn. In it he makes the connection of the little farms trying to compete with the industrialized larger farms of the wester U.S. The farmers connected the farm building into tighter quarters to make the farm more efficient.

Dairy farming is relatively new, lending itself to the newer style of lighter buildings.

Hard times after the War, did they recycle the older sturdy buildings for the general use barns, hence the remaining timbered buildings? And the big "guys" farmed and built new styled dairy barns?