I've trapped one groundhog, ever in a live trap. he was going into the coop for the chicken feed, and went into the trap baited with the feed.
Recently I talked to a wildlife pest removal person, who said that the live traps opened at both ends, placed over groudhog exits, will catch them. unbaited, looks like a tunnel to them. haven't tried it yet, but plan to.
Having a safe coop and run for overnight solves many raccoon and opossum issues, and never having feed outside of these closed areas matters too.
If we do trap, we then shoot.
Mary