German Giants aren't technically a breed, they were just a few big dragons bred together. Even if she were big, she seems overweight. How old is she? It looks like she is fed insects too often. Dragons over two years old should only eat insects every 2-3 days. The diet should be 80% salad and 20% insects.
As for the eggs, I do know that every clutch is likely to have a few infertile ones, and of the fertile ones, some of the weaker embryos just won't make it. Could just be natural selection going on with those yellow few.