I get about 4-5 eggs a day. I want my hen to lay on them. She lays on them all night & then in the mornings she's always up there. I go to work I come home, she's out with the other chickens. How long does she have to lay on them for a day? Like does she have to lay on them all day except when to get food? Her laying on the eggs enough time & heat for the day for the eggs to actually hatch in 21 days? Help. In March I'll have my chickens for a year now.