Sounds like you are on the right track. I turn eggs starting at day 1, as do hatcheries. Turning helps keep the yolk centered and feeds the growing embryos. But starting on day 3 isnt going to be harmful. As for opening the lid...eggs have large mass and don't loose temp very fast. So a quick on and off will not change the temp much. However after lock down, opening the lid will lose humidity which is extremely important for softening the shell and keeping chicks from sticking to the inside of the shell. And once they pip, you should never open the lid. At lock down, vents need to be wide open, lay down anti skid shelf liner so chicks don't slip at hatch and if needed, get a new sponge dampened, and stick it in a small cup of water inside the incubator to keep it humid inside.Really appreciate all the kind words/comments!!
Did rise up a question regarding manual egg turning during hatching days:
Some sites say turning from day 3 to 18; some from day 0 to 17; also the eggs stay vertically in my cheap model.
Can't " turn " frankly, only to tilt left/right/back/forth 3-4 times very gently/4-5 times a day.
In my previous failed attempt I did from day 3. The chicken babies did hatch very slowly on day 25/26.
The most critical days are from day 18; keeping higher moisture. Well,
Cannot add water without opening the top of the device. The manufacturer suggests " opening the hatcher always turn power off."
Well after day 18 , turning off/on for the sake of adding the water ( the only way)
I'm worried that I'm disrupting the hatching process, that why they hatched that late.
Sorry for long, grammarly incorrect text.