Backyard Fowl Keepers

Hi everyone,

Im currently incubating some chicken eggs and have been researching the recommended humidity levels for a successful hatch. While I understand the general guidelines for humidity during incubation, Im curious about how different humidity levelsboth too high and too lowaffect the developing embryo.

For example, how does excessive humidity impact chick development inside the egg? Could it cause complications during hatching? On the other hand, what happens if humidity is too low throughout incubation? Does it lead to specific developmental issues or weaker chicks?

Id love to hear from those who have experience with different humidity conditions or who understand the science behind it.

Thanks in advance!

I run a dry incubation method for the first 18 days, keeping humidity around 30-40%, then bump it up to 65-70% at lockdown. I've had great results with this approach!

High humidity can cause chicks to develop too large due to excess moisture retention, which makes hatching difficult. They may struggle to pip or drown before fully emerging.

I'd recommend keeping a close eye on air cell size. If it's too small, lower the humidity. If it's too large, increase it slightly. That's a more reliable way to monitor than just going by numbers.

I experimented with lower humidity throughout incubation and had a better hatch rate. The air cells developed properly, and the chicks had an easier time zipping. It seems lower humidity helps avoid drowning issues.

I once had my humidity spike to 80% during lockdown due to an issue with my incubator. Almost all of my chicks drowned in their shells. It was devastating.

If humidity is too high, you might get late-term deaths because the chicks can't internally pip properly. They suffocate before they even get a chance to hatch.

From what I've read, lower humidity during incubation mimics more natural conditions. A hen doesn't keep her nest at a perfectly controlled humidity level, and chicks still hatch fine!

One thing to keep in mind is that ideal humidity levels can vary depending on your location. If you live in a very humid climate, you may not need to add as much water to the incubator.

Have you tried weighing the eggs throughout incubation? Tracking weight loss can help determine if humidity is too high or too low. Ideally, they should lose about 13-15% of their weight by lockdown.