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.
On October 4, 1957, the Soviet Union launched the earth's first artificial satellite, Sputnik I. The successful launch came as a shock to experts and citizens in the United States, who had hoped that the United States would accomplish this scientific advancement first. The fact that the Soviets were successful fed fears that the U.S. military had generally fallen behind in developing new technology.