CHICAGO, Feb 2 (Reuters) - U.S. meatpacker Tyson Foods reported bigger-than-expected quarterly earnings on Monday, as strong demand for its chicken products ​overshadowed hefty losses in its beef business. Beef prices have climbed ‌as ranchers slashed the size of the U.S. cattle herd following a persistent drought that ‌burned up pastures and hiked feeding costs, shifting some demand to lower-cost chicken. The cattle herd shrank to a 75-year low as of January 1, the U.S. Department of Agriculture said ...