What would cause chicks to die like this?

[masonamacker]

9 of 24 hatched, 7 of 8 of another breed hatched.
I have hatched many chicks and have never suffered such a loss. Humidity was at 30 for the first 18 days as usual. Raised to 70 at day 18. All but 5 eggs had full grown chicks in them, i carefully removed the shell to see the membrane and none had even pipped.

 

[eggbert420]

What breed are they?

 

[masonamacker]

Lavender orpingtons. I had a different incubator full of old english game and only 3/18 hatched. They were shipped but the chicks were fully developed too. I took each egg apart slowly and it seems they were in an odd position to hatch, i was told that can happen from rough shipping, but the lavenders were not shipped. 2 different problems though. Im just not sure what happened with these orpingtons

 

[eggbert420]

Shipped eggs are harder to hatch. The other ones seemed to have drowned. Are you sure the humidity was correct?

 

[masonamacker]

Im pretty sure, i mean i know it was at 30 when i left for school in the morning, and it was around 30 when i returned home. Our humidity here is averaged around 80%, so i guess it could have rose some and went back down but that just seems a little odd. Day 18 when i candled they all seemed healthy so i doubt it was before day 18, 70% is what i normally run after day 18 but i guess that could have rose too. The glory of styrofoam incubators.

 

[eggbert420]

What is the climate like where you live? Is it humid there? I live in texas its very humid so I run my incubator dry until day 18 then I add water.