We are glad you joined our flock!
Personally, I wouldn't worry about multiple hens setting on the eggs for short periods each. I'd wait for one hen that wants to spend all her time in the nest, sitting on all the eggs she can steal from other nests, & maybe growling & pecking at you whenever you get too close. Then you can be 99% sure she's going to set those eggs 'til they hatch. I wouldn't bother with candling them either; you ever seen a hen with a candling light? She'll be smart enough to push any non-fertile eggs away. What I would do is mark the eggs you want her to hatch, & remove the others (give them to the cook), rather than have her trying to hatch a bunch of eggs with expected hatch dates spread out over a week or more; that's a recipe for disaster. If there's a long interval of inactivity, like all day, since the first few chicks hatched, the hen will likely abandon the unhatched eggs to tend to the chicks that have already hatched. Have a working incubator fired up & waiting, with proper temperature & humidity, so if she does abandon the nest (as opposed to a poop/feeding/drinking break) you can probably save them by taking over where she quit.
