Peeping chick - hen pecking it

[Broody_hen]

Hi I have a broody sitting on 5 eggs. It is day 19 and 2 of them have pipped! When I last looked the first eggs had split a little and you could see some of the chick. I didn't touch it - only looking. The hen started violently pecking at the egg like it was attacking the chick or was she helping it along? Is she stressed maybe because I disturbed her? Any advice gratefully received!