Beef packer margins improved for the second straight week, adding more than $100/head to profits thanks to record highs in the beef market. Margins remain deeply negative, however, which will be a concern for cattle markets going forward. One encouraging factor is the broad-based strength across the beef market — from Prime down to Select grades and across primals. That suggests support is not from short-term demand for a few products but rather from a sustained shift in the beef demand curve. Feedlot profit margins for last week’s placements ...