Best guesses for the cause of this bad hatch?

[Chicalina]

I had 6 remaining eggs, candled and viable at day 14, under a broody. On day 21:

1 hatched fine
1 hatched with an umbilical hernia

Day 22 after broody hen abandoned nest with 2 live chicks, I cracked open the eggs:
2 were sloshing with fluid and had quit before developing further
2 had developed to hatch, but died at internal pip.

The internally pipped ones I am confused about. Did they die from cold after being abandoned? (It was only a few hours on a sweltering 32°C day) and if so why did they take so long and not shell pip?

Did they just die in the shell and then she abandoned them, perhaps when they stopped peeping? Seems odd. They were different breeds too.

Any ideas?

 

[mcdze]

i wish i had everything figured out .. the best hatches i have done involved meticulous procedure and handling of good viable eggs from a younger but not immature flock .. if the flock isnt in 100% health and in a good stable routine and/or the incubation process isnt stable and consistent from start to finish, hatchrate goes down .. so to sum up, healthy birds, a good setup, and undisturbed incubation, which involves 'you' not overly interfering as well ..

 

[Chicalina]

Thanks for replying.

i wish i had everything figured out .. the best hatches i have done involved meticulous procedure and handling of good viable eggs from a younger but not immature flock .. if the flock isnt in 100% health and in a good stable routine and/or the incubation process isnt stable and consistent from start to finish, hatchrate goes down .. so to sum up, healthy birds, a good setup, and undisturbed incubation, which involves 'you' not overly interfering as well ..

I can't speak for the flock as they were eggs from other breeders. They were shipped, but I expect no development from postal scrambling, or quitters or issues with air cells, hence the 12 ending up down to 6 at hatch time. The two that pipped internally did so into the aircell nicely.
The broody hen has been diligent, and I did no meddling (lol, this time!). I just candled twice and left her to it. She never left the nest for more than 20 minutes.