I don't even rest shipped eggs. I do allow any eggs to come to room temperature before I put them in the incubator.Should you rest locally sourced eggs? And if so, for how long? I could only find information on shipped eggs and eggs from your own flock. I have two dozen duck eggs that I got from about 45min away and plan on resting them for 12 hours.
I have done it all the different recommended ways. None of them showed any better hatch rates for me. This is why I don't bother resting them. Other than during the turning phases, they are sitting still in the incubator. Studies have proven that turning the eggs is most important in the earliest days of incubation.Resting for 12 hours should be good. Depending on the ride they may be ok. Candle and check air cells. They may be fine. If detached rest them foe sure.
That is really bad advice. Hatchability decreases greatly after 7 dyas for most people. This is why the recommendations are to not store eggs for more than 7 to 10 days before incubating.A lady who ships eggs on her page, says she read a study that says to let an egg(shipped or not) rest 7 days after it was laid, is better than one that was just laid.