Thanks! Yeah, the ups and downs of breeding...
All the eggs looked good originally, and I did not record any abnormalities in the incubation process .
The first egg on the top left failed around 36 days, and the next 3 around 52 days.
Based on the advanced rate of decomposition of the two eggs on the left and right: I think they were duds.
The egg in the center looks like it definitely had a chance, but, failed. Could it have been poisoned by the two adjacent eggs failing simultaneously? Hmmm...Maybe.
I did note that all three eggs were looking bad at the same time, and two just deteriorated much faster than the third...I'm not ruling out interference by the two decaying eggs, but, it seems unlikely.
The cross was Gravel/Yellowbelly (Highway) x Leopard.
I only need 1 Leopard to work with, and I've got a 50/50 chance on that last egg. *fingers crossed*