Spillover selling and spotty buying interest undercut lean hog contracts soon after the opening bell. Potential buyers found no reason to "jump in with both feet" given the huge backup of animals on farms after the Christmas and New Year's holidays, a broker said.

Market longs were also on the defensive about increased Iowa/Southern Minnesota hog weights. What's more, several traders voiced uneasiness about trading February and April with the Goldman roll period set to begin early next week.

"Rather than get chopped up playing the roll game, I'll take my chances trading the back months or standing on the outside looking in," a brokerage firm's trader said.

Spot February and nearby April bulls and bears stared down one another across Wednesday's contract lows. Bulls blinked after midday cash hog prices came in lower that knocked both contracts to fresh monthly lows.

Country hog buyers foresee extended cash weakness for Friday. Packers are thought to have more than enough supplies to accommodate Saturday's 300,000-plus Saturday kill.