Beef packer margins deteriorated sharply again last week, plunging deeper into negative territory and reached their second lowest value back to at least 2010. Margins fell $144/head week over week to –$314 as fed cattle prices rose another $2.83/cwt while the Choice cutout plunged $14.20/cwt. The resulting margin compression underscored how post-holiday beef demand erosion has collided with structurally tight fed cattle availability. With boxed beef seasonally declining and cattle prices still firm, packer margins remain acutely exposed heading further into January. Feedlot placement margins improved meaningfully last week but ...