We have a Styrofoam incubator and is new to the process of hatching chicken eggs. We have had three eggs/chicks get to the piping stage, but do not progress after that and eventually die in the egg. The temp and humidity seem to be correct according to the factory. We would love to see these chicks hatch out completely. WHAT ARE WE DOING WRONG? It breaks my heart to see this happening and would appreciate any advice available.