Is that the usual color for your foxes? Ours(Chicago suburb) are just red tho straggly when blowing their winter coat. Maybe he got into poison or something. I wonder if rabies is the same in foxes as dogs. Remember reading dogs could get furious rabies where they bite at things till it breaks their teeth, and won't swerve from their path. Dumb rabies they just get paralysed and can't eat or drink, which is why they thought rabies was a fear of water (hydrophobia).