. Thank you .Good luck to you and your Silkie.
Eggs set at the same time hatch approximately at the same time (within a day or so). In that regards, it doesn't matter when they were laid but when they were set (put into the incubator or under the hen). It is always best to set all eggs at the same time to incur an even hatch and avoid staggered hatchings (much harder on a broody as she may attend to the older chicks leaving the eggs, or tend to the eggs not tending to the older chicks).
However, you may see a distinct fertility difference in the older eggs vs. the younger eggs. 2 weeks is fairly old for an egg to remain fertile depending upon how they were handled...it's about the maximum of age for setting....1 week is more likely to hatch better. It's best to set eggs within a few days. After 10 days, it gets dodgier whether they'll hatch simply because the egg cell (blastodisk) is older.
Lady of McCamley