Blessedthistle
Chirping
(Also I'm not saying I don't love dogs. I adore those sweeties! But Electric fencing has to be put up if one is around that has not been trained to be around chickens. Dogs are not scared of humans so they will not hesitate to attack the chickens, even if you are guarding them.)
My coop was built (by me) like Fort Knox, multiple locks on every door, solid walled henhouse for nighttime with steel door, buried metal apron around outside enclosure, and hardware cloth stapled, and screwed with wood over that. I moved here a year ago and the property is like a wildlife refuge, like being on safari from the kitchen window. Like you, I love watching the foxes, and there are many, so I made sure I covered all bases with the coop. Then I stupidly assumed, after seeing my roos defending the hens from my dogs etc, that no animal had a chance if it came close. Plus the foxes always watched from a far hillside and never came close, so I thought they would only come hunting at night. Well I was woefully wrong.
The good news is that after I posted I went out for another search of the property before it got dark (thank goodness I did) and my missing chicken came walking up from the pond, soaking wet and traumatized but apparently unharmed. She is drying off in my laundry room now. Fox is still working on poor Angelo....he was quite a big boy. They won't be free ranging anymore (without me there with my dog) and I will be putting up electric as soon as I am able. As always, I am grateful for the great advice offered here.