porblen hatching Dorking egg

[sthranch]

Hi,
I have incubated two batches of Dorking eggs and only one chick survived. The rest of them had some early development, some with medium development and a couple were developed but they did not hatch. Any feedback on this? I am also wondering if anyone knows much about the Dorking breed.

This is not my first incubating experience. I usually have a very good hatch rate.
Thanks!!

 

[XxMingirlxX]

How many eggs did you incubate?
How many were clears?
What was the humidity?
What was the temperature?
Still or forced air incubator?

 

[sthranch]

The first batch had 20 eggs, 7 were clear. The humidity was at 30 to 40% until day 18 then raised to 65 to 70%. Temp was 99.5 and in a forced air incubator with a turner.

The second batch had 23 eggs, 8 were clear. The rest was the same.

Thanks!