I lost 4 to the fox a couple of weeks ago. First one was at 4am under my nose - I was up dealing with a sick mare and foal at the time, in pjs and boots. I chased himup the field hoping he'd be put off by the mains electric march fence given the bluebelle in his jaws, but he got over/through somehow, ran half way up the field behind and sat there looking at me. I lost the menorcan the same day and a few yards away, it could have been any time. Buffy was taken right behind my neighbour's kitchen window sometime after 6am, and Nora, one of the original welfare trust rescues has disappeared without trace, I found feathers for the other 3 but I imagine I just haven't seen hers rather than that she's hiding somewhere with eggs, tho it would be nice.
Mine were all completely free range - I have reverted to putting them into the pen when I feed their corn in the early evening, but it isn't foxproof so I'm not sure if I'm putting them more at risk of a mass killing where free range he just takes one and the rest have time to escape, but other than those there were a further 3 broody up the barn who could have been taken and haven't so I guess he hasn't yet got up courage to enter the garden and the penning is at least keeping them from wandering up the field at dawn. It's the bolder wandering hens that have gone, not the close to home wussies like the cockerel

I had a couple of other hen deaths last week, unrelated, so am feeling pretty chook hopeless and don't know if I should just give up but most of the remaining hens are at least 3-4 years old and only one is a year old prime layer so they'd be little use to anyone else and I'd miss having them let alone the little egg money I get, so I'm doing what I can and just given up restocking that was planned for this spring/summer, at least til cubs are looking after themselves and less capable/desperate than the parent fox(es).. possibly permanently, or maybe keep replacements in secure new pens if and when I can manage that..