Are my eggs fertile

[New duck mommy 2021]

I have 2 female Pekins and 1 khaki Campbell drake. I have seen them mating many times over the past 3 -4 week
I have incubated 10 eggs and after 7-10 days there was no growth in the eggs
I had cracked open some from the lot and I thought they looked fertile but maybe I was wrong
They took a few days break from laying eggs and have started again the past week so here is a picture of one from yesterday I opened
Any help will be much appreciated

 

[BirdsBeesTrees]

I would say no.

 

[New duck mommy 2021]

I would say no.

What would I be looking for then? I think I see a bullseye when I pull the picture close. My camera isn’t the best
Here is a picture of more close up.

 

[SueT]

I see the bullseye clearly! I’d say yes!

 

[SueT]

 

[casportpony]

I think they might be fertile.

 

[Lemon-Drop]

I would say they are fertile, but I could be wrong

 

[NatJ]

I have incubated 10 eggs and after 7-10 days there was no growth in the eggs

I would say that is a much better test than trying to guess from the appearance of a cracked egg.

I can tell a fertile egg when I candle after a week of incubation, but so far I have completely failed to tell by cracking eggs (unincubated) & looking at them.