Is this odd one out still a JG, or soemthign else?

[6Happiness]

These chicks are approx 5 and a half weeks old. They were from an order where most died from the Post Office's screwing up and letting them freeze. The order had lots of Jersey Giants, and a few White Faced Spanish, Cuckoo Marans, a Bantam rose comb, and other non-black breeds.

I had 1 obviously cuckoo maran Cockerel survive, and 5 generic black chicks. I assumed the black ones to all be Jersey Giants, but as the mature, I am confused by one that is slightly smaller and the tail feathers have yet to start growing at all. (The rest all have well developing tails). The wing feathers aren't significantly shorter though as I'd expect for a slow feathering type (like the Dark Brahma we have of the same age).

So, my question is, is this slightly smaller chick, whose tail feathers have yet to start growing, still most likely a Jersey Giant? Or one of the other breeds I've mentioned above? If it is a JG, what is up with the tail... is this common? A larger version of the photo below is available here: http://fithfath.com/agangi/gallery/main.php?g2_itemId=1075&g2_imageViewsIndex=1

 

[mother o' chicks72]

Its wings have an awful lot of white on them for a jersey giant.

 

[6Happiness]

Would a white faced Spanish have wings that were that white as chicks?
I don't think they look like the Cuckoo Marans.
Otherwise, maybe the white is just because they are hatchery-stock quality.