Eggs develop until hatch time, but don't hatch

[Mike8403]

Why do chicks develop all the way up to hatch time, but never breach the air cell? I had 4 BLRW set to hatch or of a dozen eggs. Of those 4 only one hatched. I opened the eggs 5 days after they were due to hatch and noticed they could have hatched and never did. Why would this be?

 

[dekel18042]

Why do chicks develop all the way up to hatch time, but never breach the air cell? I had 4 BLRW set to hatch or of a dozen eggs. Of those 4 only one hatched. I opened the eggs 5 days after they were due to hatch and noticed they could have hatched and never did. Why would this be?

There can be various problems, but this one is always a bummer. How were the air cells? Had any done internal pips? humidity? Temperature? Have you hatched other eggs in this incubator (Trying to figure if it was an incubator problem.)
Could there have been a problem with the chickens themselves? Genetic? How is the one who hatched?
In a situation like this sometimes you can figure out what is going on if you know someone else with an incubator or broody who can hatch some of your eggs to see if the eggs are a problem. Or I you can get other local, not shipped, eggs and see if they hatch.
If you can add a second thermometer to double check the temperature that would help, but if they developed as far as they did it may be doubtful that is the problem.

 

[Mike8403]

Incubator wise, everything is perfect. My aunt is incubating chicken eggs and she's having the same problem. We had a hen set on 7 eggs earlier this year and only 1 hatched from those too. It's awfully strange