Nope, you'll be fine! I hand turn my eggs because I couldn't justify the cost of an auto turner for what may have turned out to be a one time thing (I'll be setting my third hatch today, but there's still a strong possibility I won't be hatching next year so I still stand by my logic). I turn 3 times a day...most days. On Tuesdays and Thursdays I don't get to come home for lunch, so I only turn twice a day on those days. Also, my second hatch was a staggered hatch that I started before the first one was done, and I didn't want to open the incubator more than I had to during "lock down." So they only got turned twice a day for like days 6-10 (my hatch wasn't great on those eggs, only about 40%, but I think the problem was too low a humidity). Forgetting to turn once at day 6 shouldn't affect your hatch in any way.