My recommendation is to greatly increase the number of times that you turn the eggs daily. You should also use an odd number of turns so that the eggs aren't always resting on the same side every night. There has been plenty of research done on turning eggs with the conclusion being that the...
Sorry that you are having such poor luck.
There is far too much information lacking to give any kind of advice.
1. What is your elevation?
2. Are the majority of your eggs clear or are they quitting around lockdown?
3. What humidity are you incubating at and what humidity are you at for...