I fed my bp an adult mouse yesterday, it took him about 5 minutes to swallow completely. The lump was obvious in his throat and upper body, but after he moved it down further there was no evidence that he even ate.. Is this a sign that I should start him on rats and if so, what size? Feeder rats are difficult to find here, would now be a good time to buy a pair and breed them? Or is this normal and he's fine with mice still?