Chick not breaking out of shell

[WilliamH]

I’m just curious. I was incubating eggs and I noticed on day 20th a egg was twitching. I expected that egg to hatch first but it didn’t. On day 25 the egg that twitched never hatched so I opened the egg. The chick in the egg I cracked open was fully developed. I’m just curious why it didn’t break out of its shell. Did it suffocate, got too cold, too dry?

 

[MGG]

It could have been any number of things really. It's impossible to figure it out, I've tried. Sorry for your loss