Why are eggs black when I candle them? (they're on day 7)

[FiestyFeathersFarm]

This egg is VERY strange

Very strange indeed…notice any movement yet?

 

[Silkie Princess]

Very strange indeed…notice any movement yet?

That particular one looks dead

 

[Silkie Princess]

I candled them and only left one in the incubator. It’s alive. I opened the other two and they were dead. *warning* pictures of the opened eggs attached

 

[Silkie Princess]

I left the one with the veins in the incubator and look!