I have one hen that has been secretly sitting on eggs. I recently found her sitting on 18, and I candled a few. They seem to have not overly pourous shells. They are around on week 1, day 2 as I accidently cracked one open. Now the thing is, she stays off of them for too long. Recently I have noticed that she will stay off of the eggs for 5-7 full hours, then return to them at night, and sporadically through the day. It has been very hot here lately, so they are never cool. I'm just worried. Today she did not return to the nest at all, she was off of them when I returned from school, sitting in my garage. I had to place her back in the box, and she right away sat. Is there any reason she's doing this? I don't want my babies to :/die. Tonight I will mark them with a sharpie, and hopefully I get some answers to why she's doing this.