Can chicks die because of bad genes?

[Brahma Chicken5000]

How old is the rooster? There have been hatchability/fertility problems in some araucanas. You may just have to put up with low hatchability if you want to keep using those pairings.
I realize standards are different from country to country.
Apparently your nutrition is OK.
As for seeing strange things, I hatched a chick with three legs. I thought it was very unusual and I offered it to our vet school I have a relationship with as a teaching tool. They told me it wasn't that unusual.

Did the 3 legged chick thrive?

 

[ChickenCanoe]

Did the 3 legged chick thrive?

No. The third leg came out of its butt. One of the regular legs had 6 fat toes on a curved foot. I put it out of its misery right away.
I have a picture of it somewhere.

 

[Brahma Chicken5000]

No. The third leg came out of its butt. One of the regular legs had 6 fat toes on a curved foot. I put it out of its misery right away.
I have a picture of it somewhere.

Wow that’s awful

 

[ChickenCanoe]

Wow that’s awful

Genetic anomalies happen in all forms of life. Some are good in that they may create new species but mostly, they are bad and the subject can't survive on their own. Also, those bad ones should never be allowed to breed and pass on those traits.
I've seen my share of calves, and lots of amphibians with extra appendages.
It would likely happen more in humans today without millions of dollars of medical equipment.