Bearded Dragon Calcium Question ? ? ?

Hello,

I was wondering if anyone out there has ever used finely crushed chicken egg shells to help with the calcium intake that a pregnant dragon needs?
Is this a bad idea or good?

I sprinkle my dragons food daily with her regular calcium powder and she has been getting 2-3 pinkie mice every week.

My outcome of eggs surviving this year were VERY low. I'm thinking that possibly the female did not get the proper amount of calcium before being bred. I know the egg casualties are high when they lay the first season but out of 2 batches of eggs (42) eggs total, only 6 of them look awesome. The other 36 molded and sank in a few days later.

She is 1 1/2 years old and at the proper weight to be breeding.

Thanks,
JG