You can get a modified single comb from a silkie cross. I have two silkie cross cockerels - the first one (1/2 silkie) started with a walnut comb that has morphed in to a walnut with horns at the top. The other silkie cross cockerel has 4 toes on each foot, and a single comb - he's not old enough to have much of a comb yet, so right now it looks fairly "normal". He's actually 1/4 silkie, and has about the same amount of foot feathering as the bird posted.
There's no need to get heated. I'm just stating based on known genetic facts. Certain breeds only possess specific traits, and certain genes can only affect others so much, plus there's the issue of dominant vs recessive.
Sorry, reading it back did sound more heated than it was meant to be. I'm just saying, if it's a mix your guess is as good as mine or anyone elses that have an educated guess.