One thing might not have anything to do with another. For instance, if the scar is old, more than likely it has been eating fine and whatever injury (not necessarily a broken jaw, possibly a minor cut from scraping against something sharp or scratch from a rodent). Not saying it is completely ruled out but that further investigation beyond the scar should be considered.

I think the prey item is 1. Too big 2. Not the preferred prey item. My king will gladly take mice.. I tried to give her a rat since my banana was not taking it at the time due to shedding. She striked, coiled and dropped it like a bad lemon. I tried again and she moved away. There is a different in texture between a mouse and rat as well as the smell.

When in doubt, go one size smaller in prey. I always start the size it ate before I got him the first time, then a smaller size second and third if first time it was rejected. Then work your way up again.