Possibly both are at play the issue is when an animal feed on pre-killed or F/T feeding live is a HUGE step backward.

Best way to offer F/T with a young BP is thaw at room temp near the enclosure, hold the prey behind the neck with your tong and warm it up with a hair dryer (concentrating on the head) and when offering keep holding behind the neck and move the rat around slowly to simulate the movement of a live rat (much more efficient than dangling by the tail).