Each reads about 1/2 degree below the one above
If you use all the shelves....I start a hatch on the top shelf. 1 week later, I will add a set to the 2nd shelf, a week later one to the third shelf
When you move hatch 1 to the hatcher, everything moves UP one shelf. When hatch 2 goes to hatcher, same thing....always taking those to the hatcher from the TOP shelf
When I operate this way, everything hatches on schedule (day 21)...
Also, I hatch in egg cartons (plastic or stryo) with eggs upright. Seems my hatches are significantly better this way since the chick is already oriented "upright" since that is the way we incubate (unlike a broody where an egg is on its side the entire time)