I am so sorry to hear that. Last week it was the same, I had a broody hen and a crow kept on scaring her off her eggs, because of that the eggs did not hatch and then because of that crow, or should I say magpie, hatching was an absolute disaster, no alive chicks and a hen which has wasted her whole time. With broody hens I would recommend buying a broody hen house and putting it in a garage or building where you can keep an eye on her and she would be safe from the weather and crows, or magpies.