Having problems hatching eggs...

[sunkistfarm]

I have a still air incubator...Little Giant, and it has a turner in it. It holds @ 40 eggs and I have hatched 3 bunches of eggs this summer. Each time I load it up and on day 14 I candle the eggs. I have to throw @ 10-12 eggs out that my rooster missed. I keep it at 100-102 with the humidity at 40-50. On day 18 I take the turner out and up the humidity to 60-70. But I only end up with 6-8 eggs hatching. And I had to help 2 out yesterday as they struggled for over 24 hours. They are both doing good.The other eggs have fully formed dead chicks in them when I finally give up.
What am I doing wrong??? Last year I did things the same and my hatch rate was @ 70%. Any suggestions or ideas would be appreciated.

 

[sunkistfarm]

Any ideas????? I am putting more eggs in today and I would like to get the hatch rate up.

 

[Texasmja]

Do you think the temp is to high? My Brinsea handbook says - Chicken eggs - 99.3-99.6 degrees.

 

[yo burrill]

The still airs should be a little higher.. ButI think even with a still air 102 will kill your eggs. They are very sensitive to high temps. Are they hatching out on time? Or are they early or late? Usually if they are fully formed and dont hatch it means the humidity is too high there is too much water still in the egg and chick then they are too big to move around to pip and zip the egg. If it is a styrofoam bator they are notorious for drowning eggs. Try keeping your humidity down around 40 and see if that helps. I made a homemade bator out of a coleman cooler cause I didnt want a styro bator and wanted it easily adjustable. I just have to make a turner for it so I dont have to open it three times a day.