The girls usually partially uncoil to strike and eat but stay mostly on the eggs the entire time. So far they have never damaged an egg. Last year my het pied clutch had 1 egg that was not stuck to the other and it would occasionally get away from her but she always pulled it back in with the rest. It hatched just fine.
Between ovulation and laying my girls have not eaten yet, and generally the won't eat for the weeks leading up to ovulation either. However they still have gotten back up to weight before the next season. The first meal I offer is extra small, like a rat pup, to restart their system and if they have no problem with that then I tend to offer up to a small weaner rat. I am always right next to the tub, I do not want the mom or eggs hurt. However so far the moms are pretty fast and efficient.