Unfortunately the other hens will continue to lay in her nest, and she will continue to drag the new eggs under herself to add to her clutch. Careful handling of the eggs to candle or mark them will be fine. If needed use a large kitchen spoon or ladle to aid in getting them from an awkward location, or even tongs as long as they are allow you to grip very lightly.I think she meant that her pure breds are considered petting zoo chickens because around her no one worries about breed.
On a side note, I now have a second broody starting up, she will not get off the eggs, but I made a switch yesterday, and put all one kind of egg under her, and took out her one egg, today she laid another egg (or maybe it was yesterday) I know it was her, because my other silkie has been broody for a week now, on 3 silkie eggs, and a large brown egg. Silkie number two (2nd broody) chose a very inconvenient spot, I cannot reach her, I was collecting her eggs from that corner with my foot, this is also how I pulled the egg she had laid out of her nest yesterday, before rolling the desired eggs in, I cannot get back there to pull specific eggs, and I forgot to mark the eggs that I chose anyway. argh, I'm afraid that rolling the eggs out of the nest to mark them (while she's out for her mid morning constitutional) and pull eggs that don't belong, would hurt the developing chicks. is there a point that the larger birds will stop laying in the broody's nest? or will this continue all the way through? the silkies are my only bantams