My hen hatched out 4 eggs Sunday. Today, 6 days later, I decided to try candling the eggs. 2 are completely dark, so I left them. (i know one egg was deposited by another hen a few days after she started) 2 eggs were only partially formed inside with no blood vessels, so I took them out. One egg, the one I am uncertain of seemed to be the cause of an odor, and had sticky stuff, maybe yoke on the outside. I could not candle it because it became covered in poop and maybe yoke, dirt in the last few days. I just put it in the composter but now I have second thoughts. When a chick is about to hatch is there yoke on the outside?