I am frustrated.
Perfectly formed, properly moist Narragansett turkey poult. Very active peeping, an assertive pip, followed by a 60% zip. Lots of peeping. Then silence...ominous silence. I risk opening the incubator for a moment and find the poult fully prepared for hatch, but with the outer membrane thick and leathery, and not separating from the shell. The poult's face was trapped behind the rubbery liner. Veins were fully receded.
#2 perished before hatch after about 12 hours since pip. #1, a Bourbon Red, looks like it won't make it due to blood loss.
I just hatched chicks a couple of weeks ago and everything went just right, membranes stayed soft and flexible. Humidity is up at the same level as that hatch, 71%, after incubating at 38-44% to keep air cells on track.
#1 was a shipped egg, #2 was a local egg.
It feels to me like low humidity. But the air cells were already on the small side. Last year I had wet poults when the air cells were this small. Opening the incubator door a crack to drape a damp paper towel across #1 didn't even affect the reading on the hygrometer.
There is no direct airflow on the hatching tray, and a cloth on the bottom to further diffuse airflow and catch debris. I have raised humidity to 75% based on what I see, but I see no more pips. Tomorrow is day 28 so I am not sure why these were so far ahead of the others, they were all set at the same time and incubated under exactly the same conditions.