I look for blood rings, embryo growth, and movement to make sure it is still alive. 6 more days for my D'Uccle eggs, and I am beginning to get stressed out.
Trolls steal all the flashlights in our home so I use the efficent handy flashlight on my I phone. Works great, just set the egg on top an study! I am obsessed with candling. Great topic too, cause I have a batch of chicks growing and a broody duck on eggs!