BILLINGS (AP) — A Butte-based coalition is predicting farmers in Montana, Wyoming and Colorado are on their way to getting paid for conservation practices such as no-till farming that keep carbon dioxide in the ground Ted Dodge of the National Carbon Offset Coalition believes the Chicago Climate Exchange will soon allow farmers in the three states to bundle their ‘‘carbon credits’’ for sale. The private agency trades greenhouse gases and pollutants much like other exchanges trade commodities. A spokesman for the Chicago Climate Exchange was out of the office Friday and did not immediately return a phone call seeking comment....