Day 9 is where I really start looking for blanks (ie unfertilized eggs that are showing no development during candling) because I prefer to start pulling those eggs out and discarding them on Day 10. You really should be seeing some dancing babies in those eggs! Remember to be very careful when candling, limited the amount of time you handle the eggs, and look for any eggs that may be seeping, leaking, cracked or showing any signs of bacterial contamination (which could start showing as a black splotch adhered to the inside of the shell).
On the inside of the developing eggs, we now have...
On Day 9:
- Reproductive organs begin to form
- Crop & bones continue forming