I am having trouble candling my eggs. I am trying to compare them to this link https://www.backyardchickens.com/a/candling-pics-progression-through-incubation-of-chicken-eggs some of them look like they have a black dot like the one on day 8 in the 3rd pic, i cant see the veins though is this mean it is developing? I am on day 8. some of my other eggs have a dark spot 3/4 of the egg side to side (goes all the way from the top of the egg to the bottom) is this bad? Theas are brown, green and whitish brown eggs ( they are from 3 green egg layers, black star, red star, gold laced wandolt, and think the other 2 are rode island reds or something) and if it helps when i was collecting eggs they where out side for half the day in the grass (well fed flock 1 roster 8 hens probably about 5 years old). Thanks for any help.