I am new to the chicken world, but I will just throw this out there -- Whiting True Blue?
I got my first 20 chicks from Murray McMurray this April, ordering 8 different breeds. Six of the chicks were Whiting True Blues, 2 of which were for a friend who shared the order with me. Unfortunately, being new at this, we didn't think to have MMM mark the Blues and had a heck of a time identifying them. I couldn't find much help online, so I called Murray McMurray. They told me that Whiting True Blues have absolutely no common traits other than the fact that they lay a unique consistently blue egg. We tried a process of elimination (which was further complicated by the free Rare Exotic Chick MMM offers!) I ended up taking pictures of all 20 chicks and sending them to Murray McMurray so a flock manager can attempt to identify them for me. He did the best he could, still misidentifying 2 of the 6!
All 6 of the WTB's look very different from each other (and have yet to confirm their WTB id since they are only 15 weeks old and haven't started laying those beautiful blue eggs
yet!) Anyway, your bird has the head and neck of one of my WTB's and the body of another!
I know it's kind of a crap shoot since I don't think you would come across a Whiting True Blue by accident since they are a fairly new breed and seem to be pretty rare (I think MMM is the only hatchery that ships them?) But who knows!?