Help Please with duck eggs!

[abeautifulroses94]

I'm on day 28 for my duck eggs none of them have pipped yet. I did candle them which was very hard to see anything. On a few eggs at the bottom of it looked like black veins I'm not sure what is it if anyone can help me out.

 

[JedJackson]

It's not sounding good, but give it a few more days. When you candled them, was it mostly dark in the egg with smaller air pockets, or were there smaller dark areas? Sometimes birds die before developing fully in the egg. Eggs that are clear when candling never developed at all.