First egg of 8 hatched, membrane(?) still stuck to chicken butt. Help!

[fantomas]

Sorry had a busy day today. 5 of the 8 have hatched and seem to be perfectly fine. Incubator is a brand new Nurture Right 360, and we followed the directions as best we could. Day 1-18 was 50-55% humidity, day 19-21 was 70-75% humidity. Constant temp of 99.5. Of course, after lockdown, we had a power outage. It took about 20 minutes before we got it on battery backup.