Im curious about which part of the incubation is failing....
Do you candle the eggs when they arrive and are the air sacs normal?
Sometimes shipping causes the air sacs to distort or rupture.
Do the eggs remain clear and not develop at all?
This could result from shipping damage or from infertility.
Or do they start to develop and then quit after a few days, with a blood ring?
Likely due to incubator temps or shipping/storage problems.
Or, do they develop nearly fully and then die a few days before hatch ?
This can be caused by bacteria in the incubator or by lethal genes (rare), also by lack of oxegen/ventilation.
Here is a link to a hatching troubleshooting site :
http://www.msstate.edu/dept/poultry/trouble.htm
I just candled a large batch of eggs that we have in a new incubator and saw more blood rings than I have ever seen before. Then my dd reminded me that we had a very high temperature spike just a few days into this incubation that probably caused it. Weird thing is, there are several eggs with live embryos in them that also appear to have a blood ring or a "wash" of blood on one side. Now Im wondering if the turner is working. Gaaaah.
Chel