Broodies are reputed to give out a scent which confuses predators such as foxes. We also have badgers, stoats, weasels and, polecats on the farm so I prefer to have them safe inside a coop. We had a wild pheasant on a clutch of eggs in what seemed a very safe spot between two compost bins and under a curtain of clematis and she laid every afternoon. When she finally sat on the nest the fox took her that night. We borrowed a broody and raised the poults ourselvees before releasing them, but that's another story .....