I have a broody hen that has been broody for about 1 week. Today I took her out of the nest (as she never seems to leave on her own) and found 6 eggs. I candled and found that 4 were infertile and 2 fertile. I would like to know how far along these eggs are as I am considering adding some eggs from my other hens. I have only incubated once and can't quite remember what the eggs looked like at certain days of age. What I saw today were some faint blood vessels and a black spot that I assume is the eye. Any guess how old these embryos are?