You will use as many pieces of chicken that will fit into your pan without crowding. If using Cornish hens it will be 2-4 Cornish hens halved, depending on the size of your pan.
It depends on how big it is. If you have a big enough outside chicken run to go with it (an equal number of sq. feet as the inside), you only need about 2-3 sq. feet per grown bird. If you don't have...