We've hatched plenty of chicks and ducks this year with the incubator. It paid for itself in one year, if I had spent the money on chicks rather than the incubator. I've never had any chicks hatch from a hen. We've had the ducklings hatch from their mothers and then I've taken them to raise but never chicks. Mainly it's because our chickens have always been raised in the coop and there are only three nests for them to lay eggs in. I always clean out the three nests.
This year I did a couple things different. First, I tried letting one of the hens that wanted to sit on eggs stay in the third nest. I didn't empty those eggs out, just from the first two. Unfortunately, she wasn't the only chicken who'd lay in that nest. Sometimes two or three were crammed in. I'd look under her and there would be anywhere from five to 20 eggs that she'd be setting on. The problem was, I never knew if the eggs were the same or if they were pecking them and destroying them and just new eggs were being laid. So, I started marking the eggs with an X. After a while one egg did hatch, sort of. The dead chick never made it out of the shell. After that I brought in the rest of the X eggs and put them into the incubator. From there we got the 4 chicks, although only one of them lived until I returned (that was when I had to bring the entire thing to oldest daughter's house because I had to leave town right when they were hatching).
Since we had a couple of roosters that our friends gave us that are in the front pasture, I ended up putting a couple of our hens that like to sit on the eggs out in the front pasture too. Then just recently I let our eight older chicks and all the baby ducks into the front pasture. With the sheep out there it looks like quite a farm! One of the hens laid a bunch of eggs under a downed branch and has stayed on that nest for weeks. This morning Boy was out in front and he called in to me to tell me that we have a chick. The mother hen hatched one. She was out in the front pasture strutting around with that baby! Our first "real" home grown chick. Now I know we don't need electricity to keep our chicken flock sustainable. Another step towards self sufficiency.