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 caption reads: The world's first Soviet artificial satellite of the Earth.Sputnik 1 was launched on October 4, 1957. The satellite was 58 cm (about 23 in) in diameter and weighed approximately 83.6 kg (about 183 lb). Each of its elliptical orbits around the Earth took about 96 minutes.