Are their wings smaller due to breed?

[TinyRaptorDodos]

Wasn’t sure if this went here or raising baby chicks.
But I have a bunch of few day old chicks, maybe around a week old? Anyways three have normal looking feathering while two have very very small wings. Is it a breed thing? I think they’re either barred black-sex link or barred black copper maran. Dad barred the BCM and BSL being the hens.
Thoughts?

 

[nuthatched]

Just genetics roulette.