Somewhere I read un-chilled eggs age a week to a chilled eggs day. Obviously that would depend on the un-chilled ambient temperature. I suppose if 90 F that would be about right. At normal home conditions shelf stored eggs last 3 months and more (especially if stored in basement/root cellar). Eggs go bad in an incubator in 3 weeks. I hate to think how old the eggs are in some stores. Egg shelf life varies exponentially to each temperature they are stored at. I like fresh eggs and to me that's less than a month old at chilled temperature. Really it depends on how fast you eat your eggs. Anything getting 3 weeks here and we boil eggs. Great snack food.
We do different things and different things work. First some basics. When a hen lays an egg, she puts a coating on it, called bloom. The bloom helps restrict bacteria from entering the porous egg shell. If the egg is pretty clean, the bloom does help keep bacteria out, but don't overrate the bloom. It helps restrict bacteria entering, not prevents. There is a difference. If fhe egg is dirty, especially if it is also damp, bacteria can enter the egg, even with the bloom intact. You can introduce bacteria by handling the egg if your hands are dirty. You will remove the bloom by washing the egg or by scratching it, say by cleaning it with sandpaper.
An egg will not go bad unless bacteria enters it. It does not matter what temperature it is stored at. If the egg is fertile and you store it in warm temperatures, even in the 80's, it can start to develop some. And the warmer you store it, if bacteria enters, the faster the bacteria will develop. But bacteria cannot develop if it is not present to begin with. It does not matter if they are in an incubator or not. Turkey eggs are in an incubator longer than three weeks and they don't go bad unless bacteria is present.
A clean egg stored on the counter with the bloom intact in a reasonably cool house, say in the lower 70's, can last for weeks or even months without going bad. They will last even longer in the refrigerator. Commercial operations wash the eggs and refrigerate them. They last a real long time as long as they are refrigerated.
If my eggs are clean, I store them on my kitchen counter. If they are dirty, I wash them and put them in the refrigerator.
One thing about washing them. The wash water needs to be a little warmer than the egg, say about 10 degrees. If you wash an egg in colder water, the air sac in the egg can contract. This creates a suction that can suck dirty water and bacteria inside the egg. If the water is a tad warmer than the egg, the air sac does not contract. The air sac can expand when you wash it in warmer water and create a pressure on the inside, then contract and create a suction when it later cools off, but by then the egg should be clean so no bacteria should enter it.
The paperwork I hand out (from Yahoo! Green) with new customer egg sales states that eggs are good 3-5 weeks after the "sell by date". They should last at least that in the fridge, IMO since they are fresh.
My eggs go straight into a basket on the kitchen counter. I rarely get a "dirty" egg. If necessary, I wipe them with a slightly damp piece of cut up t-shirt. We use the eggs too quickly to worry about refrigerating them.
Thank you for the information. These are my first chickens. I don't clean my eggs unless dirty and I usually just wipe the dirty spots. I have been leaving my eggs in a basket on the counter for a few days then I refrigerate.