What do you think is the optimum number of eggs in the Brinsea Eco 20? That is what I have, and I was thinking 10-12 maximum? It can get over crowded easily. My first hatch I had 9 of 10 eggs hatch. The tenth pipped but the others rolled it pip down and I thought it was safe to open the incubator not seeing the pip.
Then I hatched only 2/18 on shipped eggs. (Only4 went to lockdown). Then 13/18. I added six of my own eggs to a dozen shipped eggs and all of mine hatched and 7 of the shopped.
My final hatch was a singleton. My own egg in with 6 delivered (not shipped) eggs. None had developed at all.
Think for a while I will go back to hatching my eggs and a maximum of 12. although 8-10 would probably be better.