Oops, so sorry Heidi.
On my first year with chicken, i put my hand into the nest to double check the date I wrote on the egg. The setting hen bit my hand and ended up bitting the egg, causing a hole on the shell. I left back to the nest and it hatched later.
Since that incident, I use caution so the hen can't bite the egg. If I have to put my hand into the eggs, I always use 2 hands. One to cover her face, distracting her view while the other reaching for the eggs. I rarely do that since this can cause egg breakage so when I have to swap the eggs from 1 nest to another, I always try to do this at night.
Recently I have 2 hens setting and none hatched (maybe eggs was taken by rats). So I took 8 eggs from another nest to put under these 2 hens, four eggs to each hen and they continued to set. I decide to use both hens, since 1 may walk out later on and I will have the second back up hen to switch the eggs to. 12 more days to see the result.
I'm sure you realize that I use caution...it's breaking my heart!