So now for the bad news...
The fox came back yesterday around 6pm. Still very light outside.
It terrorized the chickens & was going hard after Cookie's chicks (my laced orps) in the tractor. (He/she was digging & clawing at their enclosure.) My kids caught the fox in the act. Two pullets were lost for a while, but were found squeezed under the big coop. Thankfully OK, just scared and stuck under there for a while until we could maneuver them out.
Three of the 11 wk olds inside the tractor got a few comb abrasions, and the 4th got hurt. The fox somehow scalped her. I feel sick. There's a flap of skin & feathers. Strangely not as much blood as I would think. I disinfected the wound & am keeping her inside for observation.
@Junibutt Did your scalped chicken live?
For now, my dog gets to spend the whole day outside, and I moved the chicken tractor closer to the house. (I think the fox is hitting the tractor because it's farther away from activity & not in line of sight from the house & garage.) At night I have talk radio, blinky lights, motion sensor spot light, a very secure coop and a hardware cloth run fastened to a perimeter of buried cinder blocks. I did not expect the fox to hit so early.
I'm obviously glad that no chickens got eaten, but I feel so bad for my sweet blue buff colombian orpington. I really can't afford a $100-300 vet bill, so all I can do is keep her clean & comfortable. Now that the fox got a taste of blood, I'm very, very scared.
The roosters were crowing & the dog was barking like crazy at something in the neighbor's yard this morning. I really hope this fox is deterred by our dog.