Once they get past 3 days old, most all of them will live unless they do something stupid. The hatch rate can vary by quite a bit. If you are hatching your own eggs from your own birds, your hatch rate should be well into the 80-90's percent. We had 7 medium hatches in a row at 100% during the late summer. On shipped eggs, 50% hatch rate is normal. That is if NOTHING goes wrong in the transportation phase.
Ok thanks. One of my chicks (5 days old) died last night.