please help infertile or not?

[OliAbc]

I recently bought some axolotl eggs online after doing quite a bit of research.
When i received the 20 eggs it was clear that some had died/ become infertile. However i am now worried about all of them. They are all mainly black and a lot of them look to of been developing well. I am worried though because all of the embryos inside on closer inspection appear to be half white and half black. The mother is a wild type black but the father could be anything e.g white, black or gold according to the website. Can someone please please help me and tell me if my eggs are ok or dead

P.s the eggs should be 9 days old

 

[Kaysie]

The white part you see is probably the yolk sac, which feeds the growing embryo.

 

[Jennewt]

A normal newly-laid egg (from a dark female) will be half white half black. However, by 9 days old, they shouldn't still look that way. They should be kidney-shaped or embryo-shaped if they are fertile and being kept at a normal temperature.