I haven't seen her today. I am concerned that it is a fox, as the chickens do roam over both (sheep and lamb)fields, and if it has taken one then it will certainly come back.
There are lots of people where we live keeping chickens that roam about and are not enclosed, and there have not been any fox problems before. We are surrounded by sheep farms and areas of nesting birds and gamebirds, with game keepers so we have never had a fox problem before.
I do not want to enclose the chickens, but at the very least I need to make the coop much more secure at night (although this one went missing during the day).
There is a good chance that she has gone off to sit. They can hide very well so she may be tucked away somewhere cosy. If you have had a good hunt about, you should probably write her off as missing in action. If she turns up, bonus, if she doesnt, its just one of those things. Unfortunately, if they roam free, its an occupational hazard. There are so many things out there that eat chickens, rat, stoat, cat, dog, fox, hawk, even crow, even if you pen them up you would never protect againt everything.