It has the wrong kind of comb for a Cornish or Wyandotte. What kind of chicks did you order in the shipment? Brown Leghorns are pretty common single combed hatchery birds. Welsummer would also be a possibility.
We ordered 2 Black Jersey Giants, 2 EE's, 1 Delaware and 1 Barnevelder. My first thought was EE but two who didn't make it had grayish green legs and this one does not. Doesn't mean they didn't drop something else in the box and just not tell me.