*Warning* Dead baby snake : (

So, I've still never hatched out a snake egg. This is the furthest I've gotten. Sorry for the sad picture, but I had a few questions about the baby. My female laid 25 eggs this year and only one egg made it to the hatch date. This one died some time in the last couple days based on when the veins disappeared. I'm really disappointed, I was so excited. : (

The temperature and humidity seemed to remain constant during incubation (I read up on all the techniques and checked at least once a day), and despite being next to a moldy egg and having a little white mold on it, it seemed to be doing well up until the hatch date. Today was the 64th day, and we would have waited longer accept that the egg had started to ooze (not sweat, this looked green) and then the veins disappeared.
Carefully opened it up and it was already dead. Seems premature or deformed or something. Temp was between 80 and 85 F so it should be fully formed by now. Any ideas what could have caused this? Just bad luck? Something genetic? Something wrong with incubation? And are the color and shape due to the baby being premature or deformed?

Thanks!

(Picture of the baby outside of the egg and the empty egg shell)

Is this your only female that you've had eggs from? Are you using the same male each time? I had two snakes that were just... genetically incompatible with each other. Had similar issues to yours two separate years with a single hatchling out of 40 eggs making it to term that died shortly after pipping from an extremely enlarged heart. Also had a 1.3 set of holdbacks from a clutch that turned out to just plain be not fertile. Their older brother never successfully fertilized an egg even when paired with females with great fertility. The male I kept produced two fertile eggs with an unrelated female, both of which made it to day 65 or so and then died. One egg had a tiny charcoal baby fused into the shape of a heart, the other had a blizzard that was severely kinked, fused, and had a deformed head. His sisters had one slug out, one became eggbound and died, and the other had a chronic sepsis that resulted in her euthanasia. That entire lineage was retired.
The female that laid the eggs with the deformed babies has gone on this year to produce 12 perfect eggs and 12 perfect hatchlings when paired to a different male.

It could be genetics. We only have the two snakes (Jack and Jill) and I'm not really sure about their genetic history. We got Jack as a baby from a petstore. He's always been healthy, but you never know what genes could be hidden away inside of him. We got Jill as a 3 year-old being sold as a sunglow at an expo (but we're pretty sure she's a diffusion because she has dark eyes). She's also always been healthy.
We weren't very good at incubating eggs (we were actually really bad) so the first two clutches she laid in previous years died quickly. We were much better prepared this year, and she laid 25 eggs but all except 3 or 4 were slugs. We lost all but the one to mold (which was really bad since we were struggling to keep the humidity consistent and it got too moist a few times).

It is not unusual for a good egg to fail to hatch. I've had eggs like that, and when cut open the embryo just quit developing. The big dilemma is what are you going to do for next season? If your desire is to produce a viable clutch you may need to buy different mates. I've had pairings such as Shiari described that never did click. The only option was to pair them differently, and luckily I had extras available and it worked out. Regarding incubating, if you follow the advice Rich Z posted you will seldom have a problem, provided the eggs were good when laid. No need to monitor humidity and make adjustments. He hatched thousands each year with his method.

Thanks for the replies! I think we'll try breeding them again once more next year, but if we have issues again we'll stop trying the two of them together.

Is the color and size of the snake indicative of a premature/under-developed baby or is it deformed (such as with a lethal condition?)

If afraid I can't tell much from the picture. If the baby was flushed off and placed on a piece of white paper with different views your question would be easier to answer. Perhaps someone could enlarge the picture to address your concerns. However, it is not unusual for a baby to have a deformity that caused premature death. The eggs I cut open that failed to hatch had babies that stopped developing, but showed no deformity.

I should mention that I have observed spinal deformities, that we call kinks, in a few babies that failed to hatch. However, I have had them hatch with the kinks too.

Here are some pictures of mine from the effectively-infertile lineage. These guys had obvious reasons why they were not viable.