Are you going to let your hens hatch chicks for you? My hens, if I let them, usually collect a clutch of 12 or 13 eggs before sitting, but you could let them hatch any amount they can cover comfortably. You will need a willing broody hen to do the work for you though and unfortunately hens are very unpredictable. Some will go broody all the time and some never does and it always happens overnight and never when you really want them to! One day they will be running around happily and the next they will be fiercely guarding their chosen nest box and threatening to take your hand off if you bother them! But if they get it right they are lovely though and broody hatches are the best IMO. We have a wonderful thread here on broody hen hatches with loads of information that I think you will enjoy:
https://www.backyardchickens.com/t/...ody-hen-hatch-a-long-and-informational-thread