I have discoverd that having an automatic egg turner does increase my hatch rates. First it turns the eggs consistently with no variation due to our busy human schedules. It turns them slowly rather than just flipping the poor little chick over real quick. It keeps bacteria from your hands off the devloping eggs. And lastly, not having to open the incubator keeps the eggs at a more consistent temperature. I do know people that get great hatch rates by hand turning also, so this is really just my opinion. Hope this helps.