You were convicted of a felony 20 years ago can you gun hunt in Michigan?

No, sorry. Once a convicted felon - always a convicted felon. Some states have methods by which you can regain certain privileges but offhand I don't know if MI is one of them - you'd have to do your own research. BUT - don't forget about the Federal Laws prohibitting it either. Violating them can get you up to 15 years in a federal slammer.