If you are using a still air, you need to rotate the eggs around. Otherwise, some develop faster.Yesterday was Day 12. I candled when adding more water. Of the 3 Dorking eggs, one is clear and one is less developed than the third one. I don't know if the less developed one is still viable. Of the 5 Leghorn eggs, same story. One is clear and one is less developed than the others. Fingers crossed for 4-6 chicks from my little hatch.