Ok, so I just went in and decided to do a bit of test candling (I know, but its so hard to not look before the 7 days are up).. I have 41 in my Hova Bator 160N Still air....Once thing that has me a bit concerned, the extreme back row of eggs on the auto turner are cool to the touch, the others are slightly, not much, but slightly warmer, enough to be able to tell the difference. I candled and the ones in the middle have veining, the ones on the back have the start of veining...I know enough to NOT make changes to the incubator now, but before I incubate again I thought about installing a small computer fan, anyone have a step by step instruction guide they could point me to?