I've noticed a similar situation with my juvie girl. She takes the longest of all my other snakes to hunt her mouse - often even and hour or two after the mouse is introduced (with me supervising the entire time)!

I offer her an appropriate-sized meal once a week. The last few times when I didn't offer her food during her shed cycle, she was A LOT more aggressive in hunting the mouse after not eating for 2 weeks.

Since she does end up eating each week that I normally feed her, I will continue to do so...however, I do have a feeling when they are hungrier they are more inclined to hunt and eat quicker. Kind of like humans, LOL!