Determining hets?

If you breed a het axanthic with a het pied you can get normals, het axanthics, het pieds, and het axanthic het pieds. But don't they all look like normals? How do you tell them all apart?

That would give you 50% possible Hets.
The only way to know for sure is to prove them out.

You can't tell them apart. Would have to prove out as 3S says

The babies would be 50% het Axanthics, 50% het Pieds, Normals, and 50% het Axanthic Pied. You can't tell them apart. The only way to know that you have hets without a doubt is if you were to breed a visual Pied to visual Axanthic. The only way you'd be able to find out what they are is if you breed them to figure out exactly what gene is in each snake. It certainly takes some time!

And that's only if you know your first pair are 100% Hets for sure.

You might be able to improve your odds on those 25% chance double hets by looking for het pied markers. At one time I heard het axanthics where more likely to be black back pattern but I'm not so sure of that one.