Bobby, using hickory limbs for cooking is just as good, if not better than, chunks from logs.
I used to have the same idea you do because I so often saw split hickory logs stacked up outside good barbeque restaurants. But a few years back, I was invited to a 4th of July barbeque out on the country (near Talladega). The old farmers were cooking a whole fresh ham. I was mildly amused when I saw them using green hickory limbs for the smoking, thinking they were way off base. Boy, was I wrong! It was absolutely the best hickory smoked meat I have ever tasted, before or since.