Incubating duck eggs

[thequackery]

I have just candled all my eggs in the incubator, discarding ones that haven’t formed at all in the first 7 days. Can someone tell me if I’m looking at a viable embryo or is it gone? I am having a hard time find information and pictures anywhere (on here or the internet) on what I should be looking for at candling stages for ducks. Thank you in advance

Basically there is a round clear(?) substance in the middle of the veins. We are on day 7 and the veins are visible but I don’t see evidence of a heart...

 

[Isaac 0]

Doesn't look fertile to me, by day seven you should see some obvious veins going on in the egg.

 

[thequackery]

Doesn't look fertile to me, by day seven you should see some obvious veins going on in the egg.

There are veins! I just focused my camera on the circular light substance instead

 

[Isaac 0]

There are veins! I just focused my camera on the circular light substance instead

If there are veins you have a developing embryo.