How perfect must humidity be? Trying for a better hatch ratio

[Blue Legs]

I am on day 14 on a batch of chicken eggs, and while candling last night I noticed that the air cells seem to be uniformly smaller than expected at this time based on photographs I have seen. The humidity level has been a steady 50-60% during the incubation period, but I haven't been able to keep it in the PRECISE 50-55% recommended. There have been a few short windows where the humidity exceeded these levels, but not for more than about an hour. Should I try and lower the humidity until day 18? If so, how much? The air cells appear to have progressed to about what most photos would say is day 7 or so.

 

[rascal66]

Humidity can be pretty flexible, but the goal is to increase the air cell. More humidity means the air cell will maintain size or barely increase size while low humidity will increase the air cell size greatly. It's not super critical to have the humidity stable 24/7.

Here is a general guide to aim your air cells.

In my personal experience, I've done humidity at 45% for day 0-18 and 60% between 19-21. In my opinion, your humidity seems a bit too high, but I know that climate can play a role in how high or low your humidity should be.
I hope this helps.

 

[EggSighted4Life]

In my personal experience, I've done humidity at 45% for day 0-18 and 60% between 19-21. In my opinion, your humidity seems a bit too high, but I know that climate can play a role in how high or low your humidity should be.

Exactly, and agreed on previous points.. except noting that climate only plays a role in how much water you must add to the bator to achieve these desired parameter inside the unit. but doesn't change their specific points.

45% for most eggs. 35% for dark brown or blue eggs first 18 days. and 60%+ humidity until hatch.

You could lower it some for now, it couldn't hurt.

You can also wait to raise the humidity until late day 19 or early day 20..

It will still draw down a lot after lockdown.. when you candle and lay the eggs down for hatching, just make the lowest dip facing up.

Happy hatching!

 

[rascal66]

Exactly, and agreed on previous points.. except noting that climate only plays a role in how much water you must add to the bator to achieve these desired parameter inside the unit. but doesn't change their specific points.

45% for most eggs. 35% for dark brown or blue eggs first 18 days. and 60%+ humidity until hatch.

You could lower it some for now, it couldn't hurt.

You can also wait to raise the humidity until late day 19 or early day 20..

It will still draw down a lot after lockdown.. when you candle and lay the eggs down for hatching, just make the lowest dip facing up.

Happy hatching!

Yep!!! My mistake on the climate bit! I recalled reading a long while ago about climate but I'm pretty sure it was exactly in regards to how much water is needed, lol.

I actually didn't know that darker or blue eggs required less humidity. But it also makes sense since I tend to see smaller air cells on my deeper blue/green eggs.

 

[EggSighted4Life]

I actually didn't know that darker or blue eggs required less humidity. But it also makes sense since I tend to see smaller air cells on my deeper blue/green eggs.

As you noted, it can vary a fair amount without actually causing early dehydration or drowning at pip.

The thicker coating on colored eggs reduces the porosity of the shells and therefore gas exchange. They still hatch fine at 45% during incubation.

While we're here, let me share one of my favorite incubation resources..

aside from our own BYC source linked here.. Hatching 101

https://www.hubbardbreeders.com/media/incubation_guideen__053407700_1525_26062017.pdf

 

[Blue Legs]

Thank you for the help everyone. I have been able to lower the humidity down to 45-50 and should be able to keep it there until the lockdown. Is delaying that a good idea if the air cells still seem small at day 18?