Chicks fully developed but die before hatching?

[JollyMonster]

My family has never had a lot of luck hatching eggs. I blamed my fathers old incubator. I recently bought a new one that is a double decker with fans.
My humidity for the first 18 days was 60-65 and my temp was 99.5°F. All the higher I could get my humidity to go after day 18 was 70.
First question. My chicks (leghorn) started hatching on day 19 and was all done by day 21. What would cause this?
Second question. I had about a 50% hatch rate. The half that didn’t hatch, all but 3 of them had fully developed chicks in them. What would cause them to die right before hatching?
Lastly, I have a double decker incubator. The bottom shelf hatched really well but the top didn’t do very good, why wouldn’t the top hatch as well?

 

[casportpony]

Welcome to BYC!
@WVduckchick , @Pyxis , @Ravynscroft , @ronott1, @ChickenCanoe , can any of you offer advice?

@JollyMonster, here are some links you might find helpful:

• The Beginner's Guide to Incubation
• Incubation Humidity

 

[ButtonquailGirl14]

HELP ME TOO!!!!!!!! i have got to have the words most broody button! i have made sure she does everything right, but her eggs never hatch!!!! when i do an eggtopsy they are always fully developed NORMA CHICKS!!! what is happening? this has happend 10 times and she isn't even a year old!!!!

 

[WVduckchick]

First,
Whereabouts are you located? 60-65% humidity for the first 18 days would definitely drown my chicks, so I suspect you probably lost some due to high humidity.
Hatching early is usually a sign of temperature a little too high, but not overly bad, since some hatched on time.

So...I would get extra thermometers and hygrometers, verify them for accuracy (google tests for the kinds you use). The meters on those incubators are known for not being accurate. Getting accurate readings would be vital for future hatches.

Editing to add - did you candle along the way and monitor air cells?

 

[Peep_Show]

I'll take a shot.
(1) Early hatching of some eggs due to those eggs being warmer. Most incubators have warm and cool spots and a degree or two can really speed things up or slow them down. At 99 degrees you might see a delay of a day or more from scheduled day of hatch. (I had Marans that were a full 3 days late in that temp range.)

(2) Humidity is too high during incubation. 40-50% for incubation and 60-70% for hatching (which will rise even further as hatching chicks throw extra moisture into the air). Too high a humidity during incubation can result in chicks not developing a big enough air cell and drowning at pip stage, so lots of fully developed chicks that seem to die right before hatch.

(3) Also might not be enough air in the incubator with all those eggs. Chicks need air to hatch and can suffocate if there isn't enough circulating. Are there more vent holes near the bottom of the incubator?

There's several articles on hatching and troubleshooting hatches here on BYC. Hatching eggs has many perilous variables which prevent the ultimate goal and give rise to the phrase "Don't count your chickens before they're hatched."

Good luck!

p.s. Maybe only incubate using the bottom shelf?

 

[ChickenCanoe]

My family has never had a lot of luck hatching eggs. I blamed my fathers old incubator. I recently bought a new one that is a double decker with fans.
My humidity for the first 18 days was 60-65 and my temp was 99.5°F. All the higher I could get my humidity to go after day 18 was 70.
First question. My chicks (leghorn) started hatching on day 19 and was all done by day 21. What would cause this?
Second question. I had about a 50% hatch rate. The half that didn’t hatch, all but 3 of them had fully developed chicks in them. What would cause them to die right before hatching?
Lastly, I have a double decker incubator. The bottom shelf hatched really well but the top didn’t do very good, why wouldn’t the top hatch as well?

The answer to your first question is that your temperature was likely too high throughout.
Thermometers and temperature controllers are notorious for being inaccurate and must be verified.
For the second question, there are many possibilities. Among likely causes are temperature, humidity, ventilation, nutritional deficiencies or heredity (lethal genes/chromosomal abnormalities).
What is the breeder flock fed?
I agree with the others that your humidity was likely too high if your hygrometer is accurate.

 

[ChickenCanoe]

HELP ME TOO!!!!!!!! i have got to have the words most broody button! i have made sure she does everything right, but her eggs never hatch!!!! when i do an eggtopsy they are always fully developed NORMA CHICKS!!! what is happening? this has happend 10 times and she isn't even a year old!!!!

What do you feed your breeding flock?

 

[ChickenCanoe]

The best thermometers I've found that won't break the bank are:
http://www.brinsea.com/p-394-spot-check-digital-incubator-thermometer.aspx
and
https://www.thermoworks.com/RT301WA

I may invest in a good hygrometer some day but in the meantime the best means of checking proper humidity is a pocket gram scale by verifying correct weight loss.
While weight loss throughout incubation isn't linear, chicken eggs should lose about 12% weight during the first 18 days.

You may want to check out the following link.
https://www.backyardchickens.com/ar...incubator-thermometers-and-hygrometers.73634/

 

[ButtonquailGirl14]

What do you feed your breeding flock?

i feed them non-medicated high protien chick starter, millet, mealworms, wild bird seed, oystershell, chick grit and sprouts.

 

[4 Georgia Hens]

My family has never had a lot of luck hatching eggs. I blamed my fathers old incubator. I recently bought a new one that is a double decker with fans.
My humidity for the first 18 days was 60-65 and my temp was 99.5°F. All the higher I could get my humidity to go after day 18 was 70.
First question. My chicks (leghorn) started hatching on day 19 and was all done by day 21. What would cause this?
Second question. I had about a 50% hatch rate. The half that didn’t hatch, all but 3 of them had fully developed chicks in them. What would cause them to die right before hatching?
Lastly, I have a double decker incubator. The bottom shelf hatched really well but the top didn’t do very good, why wouldn’t the top hatch as well?

I have very little experience with incubation, but I have learned a few things from my research. I really want you to be careful, because high humidity and wavering temps often result in splay legged chicks.