I keep my humidity at 55% to 60%. The humidity will automatically increase about 5% as the chicks get ready to hatch. I like it to around 65% for the last three days.
Question 1001 :/ - Page 2
30% to 40% is pretty low. Some folks on here have success in that range. I find that my hatch rate does the best at 55% to 60% through day 14. Also, keep in mind your temp will rise as you get closer to hatch due to the fact the chicks are getting bigger and putting off more heat. Chicks that hatch early or late seem to have have more problems. Please let us know how it turns out!