Checking fertility

[Trish1974]

I know NOTHING about hatching eggs, so if this is an ignorant questions please forgive me!

I've tried doing some research on the topic, and read that if you want to check fertility (by candling) of an egg you are incubating it has to be incubated for a certain number of days first. If I want to check fertility just by cracking it open and looking, does it need to sit around for a certain number of days or is the blastoderm/blastodisc going to look the same whether I crack it open now or wait a few days? The egg in question was laid yesterday and has been sitting on my counter for about 16 hours. I witnessed what I think was a successful breeding of the pair exactly one week ago (is that enough time for fertilization to occur)?

 

[ChickenCanoe]

Checking the blatoderm vs. blastodisc is usually best done fresh and when first opened.
The only reason to wait several days for candling incubated eggs is to see actual growth of the embryo. It is easier in white eggs. In dark eggs it may be necessary to wait 10 days.