That looks like a silkie egg to me.Yes... I'm quoting myself. After googling pictures of partridge Cochin eggs, I'm second guessing who might have laid it. Is it light enough to be a silkie!? It looks like Cochins lay something much darker.
@bradselig and @kabhyper1 , I'm looking at you two Silkie experts. I really don't think my "girl" is even old enough, but it was found in the same spot she sleeps in... Which is under the roost, but not in the "line of fire".