Chicken not sitting on eggs but eggs are fertile

[Chickenluv22]

I have 2 brodys who hatched 2 chicks about a week And a half ago and there was some more eggs but they didn’t hatch and the chicken only sit on them at night so I thought they weren’t fertile so I broke open on and it was rotten. Very smelly.
The next one I broke open was a yolk with red Veins on it...was it still alive? And the next one I cracked open had little liquid in it and had a strong soft inner shell (Zim not sure what it’s called) and unfortunately I saw a dark looking thing inside...a chick and it was smaller then normal size of my hatching chicks. and idk if it was alive but I feel bad now. The chickens only sit on them at night and not during the day since the both of the brodys take care of the 2 chicks together.
There’s more eggs though and now idk if I should crack anymore open? Would they hatch if there’re only sat on at night??
Also sorry for my grammar

 

[hysop]

I’m glad you cracked open the one that was rotten. That would have been horrible cleanup in the nest and coop.

The one with red veins was alive sorry.

The one with the small underdeveloped chick may have been alive but if it didn’t have blood I would think not.

You can try candling instead of cracking them open.

They will not develop properly or at all if they’re only sitting on them at night. They need a constant 99.5 degree F temp to hatch at 21 days.