I should add that I have incubated turkey eggs that were over a month old and had a high hatch rate.Fertilized eggs need to be kept at ambient temp. If you think about what a broody hen will do. . . she will lay eggs regularly for up to a month or so and they will sit in the nest at room temp. After she is satisfied with her clutch her hormones will kick in and she will become broody. So the first egg laid will be sitting there for a month and the last egg just a day or two. But they won't get activated until she cranks up the heat, and then they will all be on the same schedule and hatch within a day or two of each other.
If it is just a few days before you put them in the incubator there is not much you need to do. If it is longer, I usually bring them in the house and put them in a basket of bedding, and turn the eggs a couple times a day, to simulate mama sitting on the nest and turning the eggs when she is in laying the next one. It would be a fun experiment to date the eggs the day they are laid and then you could see if the fresher eggs have a better hatch rate.