Does anyone know what causes this?

[BlueO]

Hello everyone! Does anyone know what causes this? This egg is on day 22 and the veins have not closed around it on the inside. This has happened to me three times and I have never been able to successfully hatched one. How can I prevent this in the future? Thanks!

 

[casportpony]

Shipped eggs?
What incubator?

 

[Susan Skylark]

Weird air cell? Any chance they are all from the same hen/sire? May be a developmental defect on the hen’s side or the egg’s? I’ve had two shipments of saddled air cell eggs and none ever looked like that. My guess would be the egg itself (or the developing embryo) is wonky and it just can’t finish developing. Have you opened it up to see what is actually going on?