DES MOINES, Iowa (AP) — While Iowa environmental regulators hold public hearings on a new proposed rule designed to improve water quality through better enforcement of livestock farms, significant manure spills are occurring and highlighting problems the state faces managing a growing livestock industry.

It’s a difficult balance Iowa must find between encouraging livestock production that generates billions of dollars a year in sales and handling the waste generating by 60 million chickens, 20 million pigs, and 4 million cows.

The DNR is holding six hearings around the state over the next week on its proposed rule environmental groups and others say is too weak.

The group Iowa Citizens for Community Improvement says the rule should require livestock farms to obtain clean water permits to provide regulators leverage to halt frequent manure spills.