Thanks for clarifying - I was on my phone and having a hard time reading BYC.
Shipped eggs are a gamble. I have had anywhere from 1/29 hatch to 13/28, which was my best hatch. (I'm usually 90% + on local eggs) Now that I'm on my laptop, I see you are in Idaho, so probably are dealing with a change in altitude, too. I'm at 5,000 feet, so getting eggs from sea level reduces your hatch rate even more - due to the lower partial pressure of oxygen and the lack of porosity of the eggshells.
Although your incubation settings were probably just fine for your BCM, the damage done in transit is often irreparable so the eggs don't start, quit, or have a higher chance of dying at lockdown.
There are certain things you can do to help detatched air sacs re-attach, but like you said, BCMs are one of the hardest eggs to candle and truly see what shape the eggs are when they are received.
Shipped eggs are a gamble. I have had anywhere from 1/29 hatch to 13/28, which was my best hatch. (I'm usually 90% + on local eggs) Now that I'm on my laptop, I see you are in Idaho, so probably are dealing with a change in altitude, too. I'm at 5,000 feet, so getting eggs from sea level reduces your hatch rate even more - due to the lower partial pressure of oxygen and the lack of porosity of the eggshells.
Although your incubation settings were probably just fine for your BCM, the damage done in transit is often irreparable so the eggs don't start, quit, or have a higher chance of dying at lockdown.
There are certain things you can do to help detatched air sacs re-attach, but like you said, BCMs are one of the hardest eggs to candle and truly see what shape the eggs are when they are received.