I created an Excel spreadsheet with a worksheet for each of my snakes to track:
- Purchase/hatch date, genetics, and from whom purchased
- feedings - size of prey and whether the particular snake ate
- Shedding - when they go blue, when they shed, and whether it was one piece or not
- Weight - I weigh weekly and track any weight gain or loss by percentage
- Any special notes - medical conditions, etc
I believe pretty much the same spreadsheet format can be created in Google Sheets which is free.