SYDNEY (Reuters) - Australian scientists have called on the country's farmers to report any ugly sheep found in their flocks. A campaign called "Xtreme sheep" aims to study sheep with undesirable wool features to unlock the genetic makeup of the prized merino and ensure production of its high quality fleece. The South Australian Research and Development Institute (SARDI) said on Tuesday its search for "Australia's ugliest merino lambs" may hold the key to securing the nation's A$2.8 billion (US$2.1 billion) wool industry. The institute said ugly lambs -- with uneven wool, strange fibers, clumps of wool that fall out, bare...