Hens are used to getting run off nests and they will come back. The only way you might end up of having done some harm is if it is raining or cold... the eggs and drown or freeze if not properly incubated for a long enough time period. Lots of times hens will act wounded and run out in the open when they are on the nest. The idea of course is to entice a predator to chase her, and lead them away from the nest or the poults... you know what they say about a mother's love.