Smithfield Foods Inc. and its hog production subsidiary Murphy-Brown LLC last week announced that it is recommending all of its contract sow growers convert their facilities to group housing systems for pregnant sows.

The change will mean some adjustments for farmers, who wonder if the move is the beginning of a widespread trend that may impact pork prices.

"If it’s dictated to our industry that we need to go to pen housing, it will very shortly raise the price that’s being paid in the grocery store because there’s going to be a cost associated with it," said Greg Lear, a pork producer in Spencer and president of the Iowa Pork Producers Association.

Lee Schulz, Iowa State Univer­sity Extension and...