I would bet that he has Faverolle in his lineage. That 5th toe is really long and extended nearly straight back as in Faverolles. There is no indication of a crest so that rules out Silkies and Sultans and Houdans (other 5 toed breeds). The only other possibility that I can think of is Dorkins. They have long 5th toes and no crest, so that would work.