Incubation question re: humidity

[LaurenRitz]

I have a question about incubation.

I had a broody successfully hatch four eggs, and I wonder about the precise rules for incubation compared to the natural process.

I'm pretty sure that a broody hen isn't measuring the humidity. It looks to me as if she also doesn't stop turning the eggs.

So why all the important rules about lockdown?

Specifically, why raise the humidity in lockdown, when a broody hen doesn't? And yet she might have a higher hatch rate than an incubator?

 

[pipdzipdnreadytogo]

In short, because an incubator is not a hen. These 'rules' for incubation are what testing has determined works best in the decidedly non-natural environment within an incubator. A hen produces a certain amount of humidity through her skin around her eggs, which increases the longer she covers her eggs and depletes when she stands up to turn eggs or leave for a break. When she realizes chicks are actively hatching, generally she stops getting up, so the humidity builds up more. This is what we're trying to replicate in the incubator. We cannot replicate it identically, incubators and hens are just too different from one another. But we can make it similar enough to the right environment that hatching in an incubator can be pretty much as successful as hatching under a hen.

 

[LaurenRitz]

That makes sense, and also explains the feather pulling.

Thanks. So why do incubator instructions sometimes call for eggs to be placed on end? Just a space saver?

 

[Debbie292d]

That makes sense, and also explains the feather pulling.

Thanks. So why do incubator instructions sometimes call for eggs to be placed on end? Just a space saver?

I'm not sure really as one of ours does, and the other does not. I am guessing you're right as in a space saver as I can't imagine why it matters provided we keep the small end down if placing them more vertically.

I have the NR 360 which is flat, and the Brinsea 56 EX which can do them both ways.

 

[pipdzipdnreadytogo]

That makes sense, and also explains the feather pulling.

Thanks. So why do incubator instructions sometimes call for eggs to be placed on end? Just a space saver?

Yup, the hen pulls her belly feathers for better contact with the eggs.

I suspect that is correct, that it's space saving, or perhaps due to the design of the turner rails. I personally have found that my incubator eggs are a little more successful when incubated upright versus laid on their side, though not everyone has the same experience with that. Given enough bedding to nest on, my hens do seem to prefer to make a deep bowl and align the eggs around it so that the pointed end is slightly below the fat end, but not all nests are deep enough to allow for that and the hens in those nests still do just fine.