Seems like this is obvious, so I'm not sure if this is what you're asking: If it's not moving or chirping or breathing it's dead. If it is doing those things it's alive. Baby chicks begin to breathe and chirp inside their shell, usually the day before they pip. But yeah, definitely looks dead from a still photo.
The nest is way dirtier than normal for a broody nest. Probably because of that exploding egg. It does look like your dead chick made it very close to hatching, but I would not have high hopes for the other eggs if they are late and look like that. Getting gunk and dirt on the pores of the eggshell can suffocate the chicks.
The nest is way dirtier than normal for a broody nest. Probably because of that exploding egg. It does look like your dead chick made it very close to hatching, but I would not have high hopes for the other eggs if they are late and look like that. Getting gunk and dirt on the pores of the eggshell can suffocate the chicks.