I have always spaced them out as much as I could so that they have space to get out of the egg without bumping into anyone else. I also make sure the fat end of the egg is facing away from the walls, once again to make sure the chick can easily exit the shell without the top of the shell getting stuck against the wall when it hinges open. My birds have always be SUPER loud in the incubator. I can hear them chirping from across the room. So any other chicks still in their eggs can also hear the chirping for sure. And the babies have no problem running around and stomping on/rolling the unhatched eggs. So the chicks who are slower to hatch feel that movement as well.