I think that bacteria could be a large part of the problem. When chicks hatch it can leave a lot of it and incubation conditions are great for bacteria. Bacteria can invade eggs at any time, killing them and get into the navals of newly hatched chicks, killing them in a few days. This is called mushy chick syndrome. Likely the bacteria left behind after your successful hatches has been sabotaging your later hatches.
Last edited: