SHEBOYGAN FALLS, Wis. (AP) – Wisconsin’s mink farms are growing with demand for high-quality furs in China.  Fur rancher Bob Zimbal, of Sheboygan Falls, says he had 34,000 mink at his three farms a decade ago. Today, he has 54,000 breeding females, 26 miles worth of cages and an on-site feed plant.   Zimbal was among those who struggled after pelt prices sunk to $25 each in the late ’90s. He says competition from farmers producing cheap pelt overseas made it hard to get by. But today, mink pelts are going for an average of $94 each.   A U.S. Department of Agriculture report says Chinese fur processors are buying foreign pelts because the country’s homegrown furs have low quality resulting from inbreeding, high feed costs and ensuing poor nutrition.   Wisconsin is the top mink-producing state.