Lonely fox

This fox seems to be all on his own.  The den is on the other side of the back fence of our garden, in what we call the glen. He often visits the garden and over the past few years there have been several foxes that have looked like a family; two adults and three cubs, but no longer.  Over the past 6 months or longer, I have seen only this one fox.  He is quite thin and scraggy looking and is very dark in colour.