CHICAGO, Oct 5 (Reuters) - Chicago Mercantile Exchange lean hog futures rallied on Thursday, with signs of strong export demand supporting prices following the market's decline to its lowest in more than four months on Wednesday.

The United States Department of Agriculture (USDA) said on Thursday morning that export sales of pork totaled 42,900 metric tons in the week ended Sept. 28. That was up from 27,400 metric tons a week earlier.

Weekly beef export sales fell to 13,300 metric tons from 27,400 metric tons, USDA said.

The most-active December hogs contract jumped 4.5%, its biggest one-day gain since May 30. It rose 3.1 cents, breaking through its 10-day moving average, before settling at 72.275 cents per pound.

In CME's cattle markets, November feeders eased 0.125 cent to 250.3 cents per pound. December live cattle dropped 0.65 cent to 185.375 cents per pound. (Reporting by Mark Weinraub; Editing by Shinjini Ganguli)