I just recently bought an actual pediatric (baby) scale and I absolutely love it. It is designed to cradle an infant so the snake fits nicely in the cradle - you can lock the weight in place and it comes with a AC adaptor.

I did pay about $90 for it but I really like it and it will last forever.

Just google baby scales if your interested in one.

Mine was all digital so it was a bit more but some are dial readouts also for cheaper.