Another chick question

[Stormhorse23]

I have a small black chick. She was nearly identical to a black jersey giant or an australorp chick. Except now her wing feathers are growing in bright white. I am 99% sure she isn't a barred rock. Bred those for a while and her white is placed differently, she lacks a head spot, and she seems to be bigger than rocks her age.

 

[Paganbird]

Australorp chicks have white on their wings until they fully mature.