candling - my observations

OK- so after candling a LOT of eggs, I have a few observations I would like to share
I have spent a lot of time candling eggs at the beginning, enough that I can tell if an egg will develop sometimes by day 2 (white & light eggs) and of course I don't throw them out until day 10 just to be sure . I don't know how much time or effort has been put into this, so here goes.
My first observation is that a yolk will start to look elongated instead of round on day 2 if there is embryonic development.
My second observation is that on day 4 if there is embryonic development the yolk will settle to the bottom instead of remaining suspended. My eggs that have no development on day 4, the yolk looks like a little ball suspended in the middle.

Just wanted to share
If anyone wants to check it out for themselves and see how it works for you, feel free to share

Krista

edited to add that these eggs were incubated in cartons