agreed. i would settle on a smaller prey item (regardless of if you want to try frozen or live) and getting it to eat would be my first priority. 6 months...and it sounds like the husbandry may have not been that great...the snake may be very weak. if you have access to rat fuzzies, great. If not, maybe ask your local pet store if any of their rats are about to have babies and if you could get one or two of them. You could try the frozen/thawed...but after not having eaten for that long, I doubt the snake would readily go for the food. But who knows, it may readily take F/T.
Remember the most important factor in getting the snake to eat is making sure all of its husbandry needs are met: Temps, humidity, lots of hide boxes.
JonV