Yup get a kitchen scale rated for 14lbs that will measure in grams. You can find them cheap on amazon. I normally feed at the 10-15% rule. This is where you feed 10-15% of the body weight. For instance snake is 300 grams so 300 X .15 = 45grams so a 45 grams would be a 15% by weight food item. Check out this thread for the chart which is excellent:

http://ball-pythons.net/forums/showt...nversion-chart

According to the chart that would be a weaned to small rat. I weigh all my animals once a month and that determines what size they get.

I have found that BPs don't stay on hoppers for long (i am assuming mice). I wouldn't be surprised if he\she is ready for rat fuzzies or even pups right now. I have 3 month olds slamming pups like candy right now