Hatch problems

[MomGrowsFood]

Back story:

my black hen went broody with 10 eggs. Of these 10 eggs, only two hatched. When she went broody, I selected which eggs I wanted her to incubate and gave her all my amerucauna and olive egger eggs. She also had one egg that I think she laid herself. None of the Amerucauna eggs hatched. There were only a few and they got squished by another hen who decided to go broody in the same nest before I made her a new nest and confined her in it for 2 days (with a few breaks).
of the remaining eggs, her own egg hatched and one Olive egg hatched. All the other Olive eggers didn't make it.
one egg exploded early. It wasn't very old so I thought that was really weird. One egg wasn't even fertilized.
All the others died during incubation either 1/2way through or right before their hatch date.
one of these pipped and chipped the shell but couldn't get out and died. I should have helped but I've never done this before and second guessed myself.
My question is....since the mortality rate for the olive eggers specifically seems high, would this be an issue with the mother or did maybe the brooding hen just not do that great of a job? She is a first timer.

 

[Fluffy Lambs]

It is her first time but it might be something with the olive eggers. Here's my chicks today hatching:
I just read that broodys keep humidity up by dirt baths. Do you have dirt baths for yours?
Did you have hay to help keep the eggs in place?
Did you ever reach under her to make sure the eggs were actually under her and not behind her? She might have had to many.

 

[K0k0shka]

10 is a bit much for a single hen, especially a first timer. She probably wasn't able to cover all of them effectively. Next time give her fewer eggs - 6 or less.