Eggs on day 19 cracking?

[RaineyMiniRanch]

We started with 15 black copper maran eggs + 3 random fertilized eggs from then hens and put them under a persistently broody bantie we have. Her last hatch rate wasn't great but she won't stop brooding if we don't let her try.

We were down to 10 BCM eggs and 1 random egg yesterday (exploded or she's eating them...I think they are exploding). Its been bloody hot here. Today was 102 degrees.

Of the 9 BCM eggs remaining, one has a crack down it (nothing oozing). The other has a small chip of shell missing but the membrane is not punctured. What's going on?

 

[sourland]

18 large fowl eggs are far more than a bantam hen can effectively cover. Due to uneven incubation it is likely that most if not all of the eggs are not viable. Hopefully the chipped egg is starting to pip and not preparing to explode.

 

[weezyfno]

I have eggs that hatched a week earlier than what I thought because the hen didn't start going broody until two weeks ago. However, when I went to check on her in the morning as I usually do, there were a few chicks hatched. When I returned from work today, there was a total of seven chicks. She's still setting on the remaining 11 eggs.

Is it common for eggs to hatch out earlier because of the hot weather?

Also, will the remaining eggs hatch as well? I picked a couple of them up and they felt like they had chicks inside lol