Read a study looking at the hatching rate based on three options: turning the first week , the last week and the while 18 days. Guess which had the best hatch rate? Turing all 18 days. COnsidering a hen seems to always be bothering the eggs, and a turner turns, I'm gessing, 6 times a day, more is better. A minimum of 3 times a day also gives better results. GL