Does anybody know?

[Wes]

You can buy a scale from your local walmart in the cooking section that goes up to 5000 gram.
Don't know what you mean by properly weighed

+1

Get a kitchen scale from Walmart and if the snake goes off feed then just watch for any massive weight loss. That is a sign that something is wrong. Other than that, as long as the snake is eating and gaining weight, temps and humidity are in acceptable ranges, and you don't see any signs of respiratory infection (Blowing bubbles out of nose, excess mucus in mouth, dark coloring in gums and mouth, runny stool) then your snake should be fine.