Answer:
A-hunting is merely a folksy jargon- like song lyrics used for poetic license or to stretch a line- How"s this: The Banker went a-Jogging, got a hole in her noggin.. hole in her noggin... sick commentary on the Central Park Jogger affair of some years back. it is done to stretch the line- the Banker went jogging- but a-jogging is done to fit the line- same with hunting.