Which sounds low but... I set 32 eggs that started hatching yesterday about this time exactly on day 21. I just took eleven perfect chicks out, and put them in the brooding box. I candled the rest and threw out ten that were not fertile. Put the rest (11) back in the incubator which is a cheap (although it wasn't) Little Giant. When I set it up I put water in the bottom, and forgot about it. Never added any. I intentionally only turned them once a day. Some of the eggs had been outside in nests for over two weeks. I didn't clean them. I use nothing to check humidity, and I use the cheap thermometer that came with the bator. I check the temp twice a day and tweak it...so the bators range between 99 and 102 on that cheap thermometer. Of the eggs put back in the bator two have pipped, and are peeping. Since the bator was opened I know some are going to be shrink wrapped. Today I'll watch close and be prepared to help. Those I help, most live. I'm pretty sure some replaced are dead...the air sack looks too big. One egg is very discolored so I'm pretty sure it is dead. I expect at least three or four to live out of the 11 left. I expect to have 14 or 15 live healthy chicks out of 32 eggs that I broke most of the rules. I'll be happy with the 11 I have now. I have two identical incubators with turners for each one. I've been hatching for two years and keeping track of hatch rates. I have collected eggs daily and carefully stored them at room temperature turning them and keeping them only for seven days before setting. I've bought eggs...which I forgot about for two days left in the car...I've used mailed eggs, and eggs donated from friends. I've hand turned them exactly every eight hours and I've used the turners until lockdown. Sometimes lockdown happened a day or two early, sometimes a day or two late. Until now, I never candled. In all those batches...hatch rate was still about 50%. IF I had candled this batch then I'd have over a 75% hatch rate as I'd have thrown out blood rings, and infertile eggs. Some of this depends on your math. But my conclusion is that no matter what I do, or the rules I break I end up with healthy chicks out of about half the eggs laid. I realize there are folks who have been doing this for years with higher hatch rates. But with a cheap styrofoam bator, and some pretty cavalier egg hatching habits I can plan on having a hundred chicks if I set two hundred eggs. The one thing that made for dramatically better rates was to not open the incubator until 24 hours after the first chick hatches. I never tried refrigerated eggs, or eggs bought at a grocery store. I've had broody hens...they have better rates...but after some die, the hen kicks some out of the nest, other chickens or snakes kill some, and some are imperfect to start with I still end up with about 50-60% live, healthy chicks. Since I don't eat, or sell the eggs...I feed them to the dogs...I don't have much to lose just sticking them in cheap incubators and more or less forgetting them. A candler was not in the budget but from somewhere on this list were directions on making one from a clay flower pot. I made one, works wonderfully. I smoothed out the hole in the bottom with an old steak knife, and inverted in into a cookie tin resting on crumpled tin foil, and also resting a 60 watt bulb on the tin foil too. That came from an old broken lamp. I tucked black fabric in the space between the edge of the tin and the edge of the pot. It was recommended a dampened white paper towel cover the hole...but I found I did not need that. Total cost maybe five bucks...for the pot and a light bulb. But I suspect whatever one does, hatch rates are about half depending on how many you count to begin with. If you candle as you go along and throw out non-viable ones so that you end up with maybe 2/3rds of what you started with...and most hatch...is the rate you decide you had based on all the eggs, or the ones you had left after culling them as time passed.