lbradstream@timesrepublican.com T-R PHOTOS BY LANA BRADSTREAM Jeff Heiden, a realtor with New Horizons, smiles with his listing of homes. He has not seen a housing market like this in his 28-year career. Buying a home in Marshalltown is tough. Demand is no higher than it was a year ago, but the supply is exceedingly low. This market is something New Horizons Realtor Jeff Heiden has not seen in his 28-year career. Many of the listings he gets are only on the market for one or two days – then they are sold. “The interest rates are so low. A lot of people are realizing they can own their ow...