a greenfinch seen today in a private garden though seemingly in good health visually and was ground feeding well ,was plagued with a very deformed right foot, very scaly pale grey ,rather club footed would be the best description,hopping action was not as bouncy as you would imagine but as mentioned before , it seemed to be eating well and flitting in an out of nearby shrubs it didn't seem in any distress

Unfortunately this condition is not uncommon in ground feeding birds have a look at the BTO web page http://www.bto.org/volunteer-surveys/gbw/gardens-wildlife/garden-birds/disease/warts
I have seen many such afflicted birds when handled for ringing purposes.