I have black sexlinks with muffs and beards, but then again, I bred and hatched them. They are also Easter Eggers.
Those aren't spurs, those are toes. That chick has 5 toes. Some breeds with 5 toes are Dorkings, Faverolles have 5 toes and don't have feathered legs. Faverolles mix is my guess.
I agree about Faverolles mix because it explains the beard and toes.