Chicks dying right at hatch

[1 acre willows]

Just had my 3rd batch of fertilized eggs hatch 2 days ago. Of the 8 thay made it lock down only 2 made it out alive. A third piped through the shell but that was it. The rest I candled this morning before going to work and it looked like they broke through the air cell inside but that was it. Yesterday was day 27 for them which is why I candled this morning. I didn't see any movement at all in the eggs. Incubator is an old hovabator forced air style, Temp was between 99.3 and 99.7, not sure what the humidity was my hydrometer broke during lockdown. Was 40% ish most of the incubation period. The last batch i had made it to lockdown candled them then left them alone, they never made it any father. All have been turned 3-7 times a day big end up.

 

[JaeG]

Here's a troubleshooting guide that might help you pin down what's going on.
https://extension.illinois.edu/eggs/res24-00.html

Hopefully you can figure it out.

 

[Altfrizzle]

I’d try a new calibrated thermometer. Air plugs open?

 

[chuckachucka]

I think the most common cause of death at hatch is them becoming shrinkwrapped in dried out membranes due to not high enough humidity. You said your hygrometer broke so maybe the humidity wasn't high enough after they internally pipped.
The fact that they stayed in there 27 days indicates low temps during incubation. I would check that both thermometer and hygrometer are working properly next time as those things can often be inaccurate.

 

[kanina]

I'm so sorry. I feel your frustration and disappointment. I had 20% hatch this hatch. Two of my eleven eggs hatched. Not even two of the breed I wanted hatched, which was the most frustrating part. I have a cheapo incubator, but its a loaner from my grandma and this was my second ever hatch. (New incubator for next time, I can't deal with the low hatch rate and DHs thoughts on the matter any more.)

Do you use the thermometer/hydrometer on the incubator or do you use your own in addition? Do you turn by hand or have an auto turner?

If you're using the built ins, maybe they're wonked? Try your own next hatch.
If you're hand turning is it possible you're losing too much heat?

 

[lazy gardener]

Were these chicken eggs or duck eggs? Your thread title indicates that they were chicken eggs. They should have hatched on or about day 21. Your hatch date indicates that your temperature was way too low. Was your thermometer calibrated? Did the bator have a fan? If it had a fan, 99.5 would be your goal temp. If no fan, then 102 is your goal temp.

Did you have any luck with your FIRST batch?

How were your air cell sizes? Did they match up to the air cell development chart in "Hatching Eggs 101". What was your goal for humidity during the incubation period? I'm guessing that you have a combination of too low temp and too high humidity.

Before setting eggs again, if you have not done so, you should calibrate your thermometers and your hygrometer.

With a home made incubator, using the temp guidelines for "with/without" a fan, calibrated thermometers, and goal humidity of 30 - 40% during the incubation period, I average at least 90% hatch rate, with all chicks hatching between day 20 and 22.

 

[Poultrybonkers]

Im in the same boat all mine are dying the day of lockdown then breaking them open have green yolks

 

[chickens really]

Something is not right with the temp and humidity..If it's not correct things go sideways fast.
Sorry that happened..

 

[1 acre willows]

I’d try a new calibrated thermometer. Air plugs open?

All but 1 yes... the thermometer I used to constantly measure with I use at work with second one on my multimeter at work. I do heating and cooling for a living, need good functioning thermometers and sometimes 3 or 4 at a time. Mine are off by about .2 of a deg. The first batch i had hatched right at 21 days.... my new incubator arrived yesterday. I need a new hydrometer, where can i get one that will fit into a brinsea mini 2 advanced

 

[1 acre willows]

And also, what does everyone do and use to sanitize one of these?