Am I understanding this correctly--all eggs were not shipped? If so and because you got such a good rate on the bantams, I would look at the humidity; it is probably running too high. Did you eggtopsy the eggs that did not hatch in the first 2 batches?Is there not someone close to you that you can get the eggs from? Shipped eggs are so hit and miss. My last hatch (8 of 9 that I helped retrieve from their nests) were squirming in their eggs at lockdown so I am not sure what happened to the one. I like the idea of taping it closed though!
My good hatch I fixed a bottle cap to the temp adjuster, changed where I housed the bator so that there was less temp/air flow/humidity changes and did not use the egg turner so that lockdown went better. My hatches have been 1 of 7, 10 of 23, and 8 of 9. Of course the first two were large fowl and the last was bantam so maybe that has something to do with it? I also picked a thermometer and stuck with it rather than having 3 different therms and trying to figure out which to believe!!!