We have one or two red foxes here. They are small, about 20-25 pounds.
I see them trotting through in the morning.
We have had issues with possum, skunk, raccoon, and neighbors dogs; mostly the dogs though. A couple years ago, a couple dogs destroyed 50% of my flock, and the rest wouldn't lay for 7 months afterwards.
No problems with fox, but some neighbors claim they hear coyote at night. It seems doubtful to me though. There are too many feral cats in the area.