Beef packer margins weakened further last week, with estimated net losses widening to -$247/head, extending the deterioration seen through late January. Boxed beef values were firmer last week, but gains failed to offset increases in fed cattle prices, resulting in additional margin compression. Packer profitability remains well below both seasonal norms and historical averages and the outlook remain bleak with beef demand in its seasonal slump and cattle feeders holding significant pricing power in the fed cattle markets. Southern Plains feedlot placement margins declined sharply ...