if she is committed, has been sitting for a good week, only leaves the nest for a half hour or so, about once a day, stays on the nest over night, then throw some golf balls or some infertile eggs or fake eggs under her and let her sit for about 20 days. to prepare for adding chicks I would ask around and find out when the local stores get their shipments, it's usually on the same day each week. when you are ready, set up a brooder for the chicks with food and water to get them nourished and through the day that you pick them up. try and get the chicks the day they arrive at the store so they are as close to their hatch date as possible, if they grow too big, you risk them not bonding or the hen rejecting them. then that night, after it's nice and dark, swap out the eggs for the chicks, just tuck them under her wings. her heat will be the thing that keeps them sticking close and if all goes well, the bond will take and the hen will think they hatched under her. within a day or so she will start venturing out with them, take them to the food and water and start scratching around and showing them the ropes... it's one of the cutest damn things you'll ever see!