[Marches Farmer]

Just purchased one of these as spares are no longer available for my old Covatutto 54s.  I note the factory set humidity default is 20% and the instructions suggest 40-50% humidity for chicken and turkey eggs.  As 50% is actually 25% higher than 40% I was wondering if anyone else who has one could advise on what humidity level they find most successful.

[chrismahon]

The 'standard' figure used is 45% and that's what we start with. But it's all down to the porosity of the eggs and when we lived in damp houses invariably we ended up running as dry as possible after seeing that the air sac wasn't developing quickly enough. I've never heard of a problem due to low humidity, only high, when the air sac doesn't develop sufficiently and the chick can't manoeuvre to pip.

[Marches Farmer]

Thank you - I'll give 45% a try.  Many years ago the folks at the Wernlas Collection said they never added water to their incubators as they considered the UK, with its maritime climate, was humid enough to provide a good hatch and they'd found added water made the chicks too big to hatch.  Humidity seems to be a balancing act .....

[Richmond]

45% for me too, increasing to 60% for the final 3 days.