It's tough to say... Though I myself lost a few hatchlings due to the eggs being over calcified. When I opened them, it was apparent that the geckos tried to scratch their way out, but were unable to. I'm more careful with how much calcium I give the cresteds now. Mostly, I try to make sure their diets are really well balanced. Lots of good foods, gut loaded cricets, etc. And a tiny bit of calcium...and I've had no more problems with this.