So, now I'm wondering. The hen gets off the nest for ~2 hours per day. But, does she stay on the nest during "lock down?" If so, how does she know when it's time to do "lock down?" Could it be when she hears the first internal peep?
I noticed during the duration of the hatch a long, our BO hen would get up to eat, relieve herself, stretch and sometimes get a dirt bath. She would stay away from the nest for at least 30 minutes sometimes. She didn't do all of this every day but she did eat and relieve herself at least twice a day everyday up until I saw the first egg with a pip. The Silkie hen I believe would rather sit and starve herself to keep those eggs warm. I would wait until the BO was back in the nest and make the Silkie hen get up and eat and relieve herself. She would only stay gone about 5 to 10 minutes. Like the BO I could not coax her from the nest once the first pip happened. Once I saw that they would go hungry because the chicks were starting to pip and hatch, I kept food and water almost in the nest so they didn't have to get up. At this time a couple of times the Silkie relieved herself in the nest and I had to clean it up. She never did this on the eggs just on the outer side of the nest. The BO would jump out of the nest box and relieve herself then jump back in.