It should be slightly flexible/pliable for a hatchling. If you know that he's basking and has UVB and calcium in his diet, it should be fine. If it is becoming softer, changes texture, color or appearance, then you need to find out what is going on.
The marginals of hatchlings often have a little give to them, especially the scutes nearest the tail. Make sure he's got plenty of calcium in this diet (little ones especially need this for growing shells) and a good UVB light. The shells usually harden up at around a year of age.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-