we have a chicken at the moment sitting on eggs but there were too many for her to keep warm so we put some in the incubator. so far we have had two chicks hatch (1 that was already under mama chicken and 1 from the incubator) and they are both healthy and happy. this morning we checked the eggs in the incubator and saw that one had a crack in it so we put it under mama chicken. it has been under there for nearly 12 hours now and there is still that one small hole that she cracked. we have checked the egg to make sure it is alive and she is moving and chirping inside. if she doesn't hatch by herself do we assist her?