Cattle in a feedlotA strong packer margin as producer profits remain slim has prompted federal officials to revisit rules governing marketing practices in the Packers and Stockyards Act. A new proposed rule slated for release Friday outlines four criteria a processor must meet to prevent “undue preferences or advantages” to sellers that would distort market competition by giving specific market players a leg up over the competition. Any purchases must be made as “reasonable business decisions,” USDA officials said. Some industry groups say refining the rules for market competition could create uncertainty in the marketplace, while groups representing ranchers say the revised rule doesn’t do enough to protect producers’ marketing opportunities. See more on the changing regulation.