THE ACFT MADE A CONTROLLED HARD EMERGENCY LANDING IN AN OPEN FIELD OFF AIRPORT AFTER AN ENCOUNTER WITH ICING. THE PILOT WAS MAKING A TURN DURING AN INSTRUMENT APPROACH PROCEDURE AND FELT THE ACFT BEGIN TO STALL AND BUFFET AND SLOW IN ITS RESPONSE TO ROLL. HE PITCHED DOWN TO MAINTAIN CONTROL AND BEGAN A DESCENT TO LOOK FOR A LANDING SPOT. HE MADE A RAPID DESCENT TO 7500 FT.MSL & THEN SLOWED SINK RATE WITH POWER BUT CONTINUED DESCENT. BETWEEN BREAKS IN CLOUDS HE MADE GROUNDCONTACT AND FINALLY BROKE OUT BELOW 100 FT CEILING TO LAND IN A PASTURE WITH APPROACH AT 80 KTS FULL POWER NOSE HIGH WINGS LEVEL. THE ACFT LANDED HARD AND THE RT MAIN FAILED IN ROLLOUT. 100 FEET AFTER INITIAL IMPACT THE ACFT HIT A FENCE.AFTER THE NOSE GEAR FAILED THE PROP DUG IN AND THE ACFT NOSED OVER 156 FEET FROM TOUCHDOWN. THE OCCUPANTS WERE NOT INJURED AND MADE AN EXIT FROM THE ACFT THROUGH A WINDOW SINCE THE DOORS WERE JAMMED SHUT.