I have the Brinsea Oct 20 Advanced and my humidity has been at 40% (99.5-99.7 temp) for the 18 days (one channel full)...it's been fine - all eggs developing. Actually they say in the book anywhere between 40-50% for the first 18 days and then 65%+ for the last 3. I haven't tried to achieve that yet but we'll see what happens when I fill both.
We have a big wood stove as well but I am fortunate to have a door to shut. I filled both, do you have a humidifier you can put near the incubator? If not, do you keep water on the stove? That seems to help me a bit. Some people put down wet rags to try to increase the surface area. -Cortney
Progress! I would take a knife (that's what I use) and turn the temp up just a bit. Tiny change, and watch it, if its not enough a tiny bit more. I leave that piece of the top off so I can make needed adjustments. Kids to school? Its almost 2am here!
By the way I love the chickens you are hatching, simply beautiful! Wish I had some in the states. -Cortney