Does "bullseye" remain after a week of incubation?

[pawtraitart]

How well does the bullseye hold up after the egg has been incubated for 7 days or so? Will the definition remain or kinda melt away? How can I tell if an egg was infertile to begin with, was fertile but didn't start, or started but stopped early?

 

[Dipsy Doodle Doo]

Hi! In eggs I've been shipped, I cracked the clears on Day 6 to check for bulls-eyes / fertility. *I* could tell fertile from non-fertile. There were eggs with loose air cells (aka 'scrambled'), that had perfect bulls-eyes, but didn't develop because of rough handling.
On Day 7, it should be as distinguishable as Day 6.
Good luck!

Lisa

 

[pawtraitart]

That's what I need to know. Thanks!