Hi , We set three eggs under our broody chickens and yesterday was day 21. In the night one little chickie appeared but nothing from the other two. They seem the same in appearence as the one that hatched and the mummy chicken has not discarded them but no cracks have appeared. I think i can hear movement inside and am convinced i can hear tapping ( although my husband thinks i'm mad !) What do i do ? do i intervene and make a small nick in the shell or just leave well alone ... and if i leave them how long do i leave it before removing them from under her ?