I have broody hens incubating clutches of eggs in several locations. Dogs know where all the nest are located. Normally the dogs pay little mind other than to walk over and sniff general area before moving on. A different reaction occurs when the chicks are hatching as the dogs cock their heads and orient on the nest for a lot longer. Could be possible to train dogs to notify me of hatch when records nor kept close enough. Also indicates predators could pick on same sign to located nests.