When I skate, why does my right ankle turn in more than my left?

I have heard someone say that it could be because my skates are too big, but not only was I fitted by a trustworthy hockey shop, my right foot (the one turning in) is more than a half size bigger than my left foot. If I look down, my left foot turns in what seems to be the correct amount, but my right is almost twice as much inward.