Fertilized chicks dying in the shell

[GrandmaCyndi]

I have an 18 egg incubator. The last 3 hatches I've done I get 1/3 hatched and healthy, 1/3 ended up being unfertilized and 1/3 formed but died in the shell.
These are all from my own chickens, not bought or shipped and all less than 10 days old at incubation.
Any ideas on why chicks are growing but dying before hatching?

 

[Tex452]

How many hens/rooster do you have?
Do you live in a high humidity area?
I got eggs from my son that has a good hens to rooster ratio, I hatched 20 out of 21 fertile eggs.
I got eggs from a friend that had 1 rooster on 27 hens, I got 8 fertile eggs out of 22 eggs, all 8 hatched.
I live in a high humidity area, and I do the 100% dry hatch method, no water added at any time, so far I have a93% hatch rate or a little better.
I hope this helps.

 

[Susan Skylark]

Look for egg stresors preincubation or during early incubation: greater than ten days old at start of incubation, heat or cold stress (a couple hours outside at below 40 or above 80 might be enough to cause issues), incubator temp spikes, turning issues are most common (and in other cases shipping!). Genetics and nutrition of source flock are possible issues but secondary as less common. Infertility and high embryonic death rate are separate issues, don’t worry about rooster ratio when dealing with embryonic death issues. Humidity is not a huge contributor either. Stable incubator temp, appropriate turning, and being kind to your preincubated eggs are the most important factors. Test your autoturner or hand turn, use a couple external thermometers and watch them, collect eggs often during hot or cold weather, will increase your hatch rates, also open dead eggs and figure out when each embryo died: early or late incubation, are there abnormalities, etc.