There are so many bad rumors about eggs.
Most likely spread by the big egg companies to get you to buy inferior products when compared to what you can get locally or have ready in your own back yard. It's the same tactic used to make everyone buy bottled water that was most likely bottled from your municipal water sourse.
Like they say just keep them at room temperature.
If they sit at incubation temps (over 94 degrees and under 102) for more than a day its likely the development cycle will begin.
Still, the egg wont show much change until a couple days have passed.
Most importantly you can eat the egg and all contents at any part of the development cycle, so long as you dont mind the look of it.
The only "bad" thing about any egg is if it si rotton, or if you dont want to eat a baby.
Some people really do want that baby bird, in the Philippines its quite popular.
(not for everyone, but it proves a point)
http://en.wikipedia.org/wiki/Balut_(egg)
You see Balut stands EVERYWHERE you go in that country.