Three sheep were shot dead and six are missing from a Sebastopol winemaker's vineyard high above Napa Valley on Mount Veeder in a rare attack on livestock, Napa County sheriff's officials said.The dead and missing animals were rented from a Suisun Valley rancher to munch down the grass and weeds on Tom Meadowcroft's three acres of cabernet sauvignon vines off Mount Veeder Road a few miles south of Dry Creek Road.