Here is what i found... The incubation period for a guinea fowl egg to hatch is 28 days. The length of the incubation period can vary between 26 and 30 days, if the temperature or humidity is incorrect in the incubator. The correct temperature in the incubator is 37.5 degrees Celsius or 99.5 degrees Fahrenheit, decreasing to 36.5 degrees Celsius or 98.5 degrees Fahrenheit during the final three days of incubation. The correct humidity is 65% until day 25 and then rising to 80% until day 28. Is this all correct? I have never incubated them before. Please give me your advice! Thank you!!!!!