GNP, maker of Gold'n Plump chicken, said Monday it plans to expand its Cold Spring operation, a project that could eventualy increase capacity by one-third.

The first phase of the expansion, which began earlier this month, is expected to cost $35 million and includes a building addition and new equipment.

Plans for the expansion's second phase, which would also include a building addition and new equipment, are still in development.

If both phases are completed, annual production will rise by an estimated 33 percent, which equates to 88 million more pounds of processed chicken, GNP says.

St. Cloud-based GNP did $452 million in sales last year, a 13 percent increase over 2013. GNP was purchased in 2013 by southern Illinois-based The Maschhoffs LLC, a large hog producer that bought GNP to diversify into poultry.

The expansion shows the commitment of Maschhoffs and GNP into investing in the company's growth, GNP President Steve Jurek said in a press statement.