Have 4 hens and 1 Rooster. Two are now sitting on eggs (I put the date) and we'd like to have the grandkids experience hatching. Do they sit for 21 days w/o eating and drinking? Can we combine the eggs so only 1 hen sits? Can you take the hens out to stretch and eat?? What happens once they are hatched. Do they care for them?? Do we need to separate the chicks from the Mom or the others?? Thanks!!!!