6days in incubator ,clearly an embryo but no veins? Help

[krisserk]

Hello, as first timers using a still air incubator , I was hoping someone could give us some insight. We placed 20 brown and, 3 green eggs . in a still air incubator 6 days ago. We were super excited to Candle them today. Seems as though temperature stayed regular at 99.5 .so we aren't worried about that. Our concern is because all of the eggs are brown we are clearly seeing air sacs and possible moving embryos but are struggling to see any veins. Is it really that hard to see veins on darker eggs? Should I let them for a few more days before deciding what to do? And if nothing is changed, suggestions are welcome.
Thanks in advance

 

[SunHwaKwon]

What are you candling with? Try a brighter light and make sure you are candling in the dark.