I came back from holiday to two hens sitting. One grey hen, and one white hen. Two days ago i checked in on them and my black hen was sitting on the white hen's eggs and the white hen was kind of still in the box sitting. At first I thought the black one was just laying an egg since the black hen was on the roost for bed and the white hen was on her eggs. Then yesterday I went to check on them and the black one was sitting on the grey hens eggs, and the grey hen was sitting on the white hens eggs and the white one was on the roost all day long, then at night they all switched back again to the original places! Same thing happened today, but only the bkack and white hen switched, and i was even there this evening to watch them change shifts. I am worried that i will losesome chicks if they dont get serious about staying on a nest. Do hens sometimes share a nest like this? Its so bizarre!