Consider changing the way/ method that you use to thaw, warm, and present the prey to the reptile. Yes, We’ve been under the mindset that males don’t require anything larger than a small rat but in the wild they take pretty much whatever comes their way. So I don’t believe that any snake is afraid of any rat. The food chain just doesn’t seem to support that idea. The reptile is probably being more cautious and sizing up his angle of attack. I would re-evaluate how I’m presenting it to him/ her. Try increasing the interval that offer food as well.