What is wrong with this dove? - Update

 

This dove turned up in my garden in this condition the other day.  He is feeding well and able to fly ok, but he looks dreadful.  There are 5 doves that come into my garden and the love triangle from an earlier post still continues, but they ignore this one.  It seems to scratch a lot, do they get mange?

I've learned that I still have a lot to learn...

http://www.flickr.com/photos/bramble67/