I have two hens who have decided to use the same nesting box (12"x12"x14"). Between the two of them they have laid 20 eggs in the box and were both sitting on them. I candled the eggs and saw the beginning stages of development, but then for some reason the embryos keep dying. Two chicks hatched last week and one hen is taking ownership of them. The other was sitting on the 4 remaining eggs. Expecting that they should hatch any time, I just candled them again tonight and found that two more were rotten. It seems that they've not really gotten past the second week of development before dying. Any idea why this is happening? I can understand if I'm incubating them that the temp and humidity play major factors in this, but with the hen sitting on them, I'd think they'd be okay. Is it possibly getting too hot with two hens sitting in the same box?