If you’re going to incubator hatch regularly you need to get a good incubator period. I use the tractor supply nature right, it’s kinda pricey but worth every penny. I’ve hatched hundreds of chicks out of mine so far and not had any issues with it. I set the temp to 100.5 and leave it alone. 1st week I don’t even look at the incubator. 3 days is too early to tell, I 1st candle the eggs at 7 days. At that point you will have no problem telling which eggs are good and which ones aren’t. But seriously get a dependable incubator, you’re going to save yourself a lot of stress and time.