Fertility of the new eggs

After a few days I candled the eggs and could see one of the 6 is fertile. It had a black spot right on top. A couple of days later 2 more eggs showed sign of fertility and today I saw an other one. 2 eggs still look like buds, but nothing is lost yet. They develop in different speeds. Unfortunately the cam batteries were empty today when I candled, but I will upload pictures tomorrow and show the different growing process. The first fertile egg I found, has already a dime size spot today, while the other ones are still just a big bigger than a needle head.