You can store eggs at 55 degrees Farenheight and 75% humidity for seven days before putting them in to hatch. I don't have such a place so I've always just put mine in every day for three to four days. The chicks in first hatch really well but as the days go on, the percentage of hatch decreases. I'm trying this to see if this year I can change that.
I'm wondering if it is due to the drop in temperature when you put new eggs in for they need to be warmed, hence, the idea of putting them in a heating pad and warming them up first. This is exactly what the experts recommend if you put in eggs that have sat at 55 degrees. Just not the heating pad method but it seems to work pretty good for how else would you do it. You aren't suppose to stick them in water and definitely not the microwave.
I don't get but eight eggs maxiumum on any given day so after a few days, I had to stop even though the incubator wasn't full. Besides, what am I going to do with all those chickens anyway. I have asked a couple people and they want chicks. So there goes a few extras. Now I need to learn how to sex, day old chicks. That ought to be interesting. I know the principle but I've never tried. I usually just make guestaments and when something crows, I mark it for sure for the freezer.
If you haven't bought a incubator before. I do recommend perchacing the egg turner. My first one did not have one and I had to turn eggs at least three to four times a day for 20 days. It takes 21 to hatch chickens but you don't turn the eggs the last day. Ducks are 28 days.
When you choose eggs, don't pick the small ones because they will be small chicks. Don't pick the really big ones because the chicks won't be hardy. Not the warped shaped ones or really bumpy ones either. And definitely not the thin shelled ones. They won't hold enough moisture inside the egg. This is why before I plan on collecting, I'm extra conscience of keeping some oyster shells in the coop for calcium.
Another thing I do is feed lots of wheat for the high protein since a large part of an egg is protein. Now I don't know if that is what a science guy would do, but I do because it makes sence to me.
Now to keep any little grand kids hands from turning the dial on the incubator and changing the temperature. Steady as she goes at 99 degrees F. Also I need to keep the humity up so I do not cause crooked toed chick. Genetics and wire bottom cages are other causes for crooked toes.