Fertile or not? Day 4 candling

[MGG]

second and last may just be behind, as mentioned double check day 7. The third is definitely not doing anything. Usually I can see the beginnings of changes around end of day 2-3, darkening of the yolk, sometimes a darker line, but no veining til day 4. If any of those are blue eggs, I do find they’re harder to see details through early on.

X2. 3rd one is the only one that really looks infertile, the last one looks like it could be developing too. With blue eggs, it's best to wait until day 10 to toss any, just to be totally sure.