my method evolves every time i do it .. it varies with time of year and ambient temps to .. also condition of the flock plays into it, their age, how many, etc ... eggs should be fresh and good condition, from my own flock ive learned to spot likely duds .. but basically get the bator stable at a target 99.5 and 60 humidity while i collect up a batch of eggs up to 5 days on the counter, then drop them in .. candle at the mid point to get rid of clears .. then wait till day18 or i see a pip to remove the turner .. if the eggs are good to start with and temp can be held steady and even itl be close to 100% hatchrate ... the wild card is egg fertility mostly, you need fresh healthy hens and a good rooster to get a high rate of fertile good eggs .. temp can be difficult to hold steady at certain times of the year which affects hatchrate, mainly, try to avoid over temp .. in other words, dont set up the bator in the evening or in a cool house to 99-100 and then have it bump to 102+ midday .. its not uncommon for me to adjust it a few 10ths up and down if temps are swinging alot, i keep an eye on it, mainly if im hot or cold, i know to check the bator temp ..
