This hunting begins at the sheriff’s office, where you’d have to catch an outlaw, either dead or alive ... as medical supplies. Read the wanted poster and accept the mission.

As of 2011, it is available as DLC (80 MSP on Xbox Live) and is included (free) in Red Dead Redemption ... You can find Moe van Barr's Wanted Poster in Armadillo. Just stick around the town ...