Oh and I have rarely seen movement later into the incubation. I do sometimes, but I thought I had lost a bunch on thursday and all but 3 eggs hatched, so I have a full brooder. Never think it's not going to hatch. So many people have tossed eggs or broken them open only to find they would have been fine.
They have to be at an eleveated temp for several days or throughout the incubation to hatch early. When you candle, you probably won't see any movement this close to the hatch. They simply don't have a lot of wiggle room.