I started to check boxes, then realized I checking almost all of them. I seems that if you do enough hatches, particularly if they involve shipped eggs, you will eventually encounter just about every problem out there. Sometimes it is incubator or broody hen error, sometimes its rooster error (infertile eggs), and sometimes it's just poor egg quality.
Generally speaking, shipped eggs are the worst culprit. When I use fresh, well-shaped backyard eggs I generally get hatch rates of between 80 and 100%. Shipped eggs have been wildly divergent and have yielded anywhere between 0 and 75% hatch rates, with a lot more cases of chicks hatching with open navels, or not being able to complete the pip and zip process.
Generally speaking, shipped eggs are the worst culprit. When I use fresh, well-shaped backyard eggs I generally get hatch rates of between 80 and 100%. Shipped eggs have been wildly divergent and have yielded anywhere between 0 and 75% hatch rates, with a lot more cases of chicks hatching with open navels, or not being able to complete the pip and zip process.