An egg that has been pipped since Thurs night is probably in trouble. Is it making any sounds, or rocking? If it's not as active, you might want to assess the situation and decide if you want to help it out. I know that there's a lot of controversy about helping chicks out of eggs. My view is this: Incubation is not a natural process, we're muddling along, trying to duplicate what hens have been doing for thousands of years, and their their system has been perfected since day one. So, if i have a chick that is not doing well, my inclination is to help it out, knowing full well that it may end up needing to be culled in the end, but at least i will have given her a fighting chance. Of my 2 assisted hatch chicks, one died, (mushy chick with peritonitis) and the other is doing so well that i can't tell her apart from her 4 sisters. So, if you help her out, she might live, or she might die. If you don't help her out, she might hatch without any problems, she might have some problems, or she might hatch and die. Your decision. I've heard that some hatcheries just toss all eggs that haven't hatched by the target time, even if they are in the process of hatching. No right or wrong here, you've had a good hatch. Anything else is gravy or a learning experience.
In the future, i may adopt a more hard nosed approach, culling those chicks that don't hatch strong and well to keep my flock strong, but until i'm breeding my own birds, that's a moot point for me right now.