Fertilized chickens eggs

[The Honk]

If I bought fresh fertilized eggs from a good source, what is the maximum time they can be kept before being incubated?

[red]

i dont know what the max is, but i think they will be good for a week or two. My friends have even taken them out of the fridge and incubated them successfully!
I think optimun time is about 4 days old (day old are not supposed to be as good for some reason).

store them blunt side up, or on their side and turn 3 times a day