Wow, no clue, but here are 2 wild guesses: Either a partridge (do they come in that color?) Cornish, or a turkey poult of unknown type. Color is really unusual.
Could you get a better shot of its comb and body? Does it have a tight rosecomb, a pea comb? I can't really tell from this angle other than it possibly being a Wyandotte, or an EE, or just something else. . . Head almost looks non-chicken.
Where did you order from and what else did you get? The rest look like Cornish, which is what I just ordered from McMurray, and I have a little guy that has similar coloring...so I'm interested too! Did your freebie have a striped chipmunk like back, and a feathered foot when he/she first came?