I think they're Black Australorps but I'm not sure

[EllaTheQueen6]

I have 4 chicks, 4-5 weeks old, and I got them from a friend. They told me the breed but I completely forgot and I don't wanna ask the friend cause I'd feel silly. I do think they're Black Australorps but I'm not entirely sure. It would also be cool if you could sex them, but I doubt you can, I mainly just wanna know the breed. Please and thank you!

 

[paddock36]

My guess is also Black Australorps. I think I see two roos due to the redness in the comb, at least one pullets but I can't tell for sure on the last.