They can go in incubator now. They can be put in incubator 2 days after set or up to 8 days. The duck egg that was layed yesterday can be but wait a day or 2 for the newer ones. I would wait a while until you have a clutch of eggs that are needed, the eggs will be fine up to 8 days.
At last, on January 31, 1958, the United States succeeded in launching its first satellite, the Explorer. The Explorer was still slighter than Sputnik, but its launch sent it deeper into space. The Soviets responded with yet another launch, and the space race continued.
The first satellite in space was Russia's Sputnik satellite, carried by an R-7 rocket. The R-7 rocket was built by a team of German and Russian scientists led by Sergei Korolev. Sputnik was placed into orbit on October 4, 1957, months before the first U.S. satellite, Explorer 1. Korolev's team managed to create a rocket big enough to take Yuri Gagarin into space. Gagarin became the first man in space, but the U.S. astronaut, Neil Armstrong, became the first man on the moon. Learn more about Space Travel