My mom has 5 chickens and a rooster, all at about 6 years old. 2 chickens are sitting on a total of 13 eggs. Sometimes another chicken will sit in. They have been sitting on them now for about 23 days, and so far nothing. The chickens are acting like they think it is closer by constantly checking under themselves, and continually covering the eggs around them fully with hay, more so in the last few days. Does a chicken know they should continue to sit, or will they know a time period to abandon the eggs. Might be a silly question, but I am curious. thankyou.