drawing a blank help!

That depends who you talk to. I run mine 45% during incubating with 40-50% being acceptable and 60-65% during hatching. Some will run as low as 30% to as high as 55% during incubation and still have success. It seems to depend on your climate and incubator.

 

Quote:Much of the confusion arises because it's not humidity that matters, it's weight loss.

An egg needs to lose around 13% of it's setting weight by day 18. It does this by evaporation through the shell.

The humidity level affects this rate, and that is why we use RH as a measure.

However, not all eggs lose weight at the same rate, shell thickness being a major contributor.

So, if we were being technical, we would check the weight loss daily, and adjust the humidity to an appropriate setting.

We go for averages, so average eggs stand the best chance. Usually that is good enough; sometimes it lets us down.

By the way, using a weight loss technique, and charting the results makes a great school project.