It's variable, lots come in to play

Weight out of the eggs, I have hatch some in the 40+ grams and some in the 80+ grams.

How fast they start eating, some will start the day of their first shed some might take 4 or 6 weeks before getting started.

So imagine a 40 grams hatchling that take 6 weeks to take his first meal and compare it to a 80 grams hatchling that eats right away, the difference can be pretty significant.

What matters is that your animal is eating and that he LOOKS healthy.