This is our first time hatching chickens. The first two hatched this morning with the third hatching about 3 hours later. The 2 original chicks are a bit bigger and seem a bit aggressive to the new smaller chick - is it normal?
The first chicks that hatch always end up pecking on the new ones. If there's no blood, don't worry. Some people like to remove chicks from the incubator to a warm brooder immediately after they hatch and become active to prevent this.
It all depends on who you talk to. Hatching humidity is a tricky thing, and some people prefer to run at 60% and leave the incubator closed until all have hatched. Some people however, bump hatching humidity up to 80% to allow some wiggle room to remove chicks. Of course holding the cover off the incubator is not good, but quickly slipping a hand inside to pick up a chick may not be all that bad if you can keep the humidity above 65%. I personally try to leave the incubator closed, and remove chicks at the end of the hatch, but have observed that adding several rags, saturated in hot water, brings any lost humidity back up almost immediately. Good luck with your hatch.