You can get a gram kitchen scale from walmart or target for about $20. Just make sure they can go up to like 5,000 grams or so.
If that is the reason why you want to keep the mice (small babys) then I would try and get a colony of African Soft Furred rats (ASFs) they are pretty small as babys and when they are full grown they make great meals for adult ball pythons.
Great, Thank you!
Just bought a 5000 gram scale on eBay. Now for the Rats, if I cannot get ASF locally will normal "Fancy Rats" be ok? This is assuming that I can get my snake to take them after eating live mice.
Yeah a normal rat will be fine. I was just trying to kill two birds with one stone for you. A prey item that will grow to the size of a small rat for the ball python, and a baby that will be small enough for your bearded dragons.