Broody hen abandoned eggs

[Mtnboomer]

I had a broody Brahma that had a case of cold feet for motherhood. She abandoned her eggs yesterday and again today, leaving them uncovered for more than 6hrs a day during a typical mountain spring day that barely reached 55 degrees.
I have had this problem before each time one of my hens go broody. To ensure they stick it out i usually lock them in the nesting box with food and water and it usually works.
This time she quit before i could get her secured. This evening she was in a different box again with eggs under her. I discarded the original 27 eggs she was sitting on and locked ger down with 6 fresh eggs.
I have never had a brahma stay on the eggs long enough to hatch without locking her in a box. Is this typical if the breed? What factors make them abandon the eggs?
Ps. All the hens locked down until hatching have been Excellent mothers to the young

 

[Yardmom]

Wow 27 eggs may have been a bit much. Is she staying on the new eggs? I don't have braham. I have had a hen stop being broody the day before hatch. She was caged in the coop, but she tossed the eggs around. I saved one with the incubator.

 

[Mtnboomer]

Wow 27 eggs may have been a bit much. Is she staying on the new eggs? I don't have braham. I have had a hen stop being broody the day before hatch. She was caged in the coop, but she tossed the eggs around. I saved one with the incubator.

She is now locked in with them. She is sitting very well with another 12 eggs under her.
My broodies (4 different birds in last 4 yrs) give up every time at around the 8-10 day mark. But when locked in with no choice they are excellent at hatching and are great moms.
I was just thinking that with multiple birds, from multiple generations, and each year during different seasons its always the same result (if not locked in) that perhaps it was a breed thing?

 

[ChickenCanoe]

How long had she been sitting on the original 27?
I don't think I've ever had a hen able to cover that many eggs.