Hi everyone, I am new here and am searching for some informational help please. I have 26 hens and I recently bred 3 of them. They were all buff orpingtons. I stored the eggs in a cooler at 55 degrees faren. constant temperature. I put all the eggs in the incubator on last tuesday. It is now saturday (4 days ago). These are all brown eggs. I candled them today. What I see in 12 of the eggs is a large dark area that floats as I rotate the egg on its side. They are all laying on their side in the incubator. I am not for sure what this is that I am seeing in these eggs. At first I assumed it was the baby chick forming, but I do not see any veins in any of the eggs yet. Then I assumed this must be the yolk that I am seeing floating around in the egg. But now after reading some other posts here, I am assuming it is the air sac floating around. Does anyone know what this is that I see floating in the eggs? The rest of the eggs appear clear as I do not see anything yet. This is my first time to breed my hens and set eggs.