I might take to peak to make sure the chick isn't glued to the shell. I've had that happen a few times where the chick started to zip and froze partway round.If there is any movement or noise coming from the last 2 that are not pipped, I will give them some more time in the incubator - no plan to assist until there is an external pip. The one that is backward and already externally pipped has zipped about 1/2 an inch, but seems to be having trouble moving to continue to peck around the egg.