7.5 week old chicks, mixed breed gender guess

[Boldriniewy]

I have 4 mixed breed 7.5 week old chicks, not certain at all of sex. First time raising chicks. Would like to have any guesses for sex of the red chick in photo and the black chick in second photo. The chicks prominently in the front of each picture. The lady I got the 3 day old chicks from, raised in incubator, and doesn't know breed of rooster or the hens that laid eggs. She just gathered eggs and incubated from a very diverse group of hens. If you guess the sex you think these birds are, I would appreciate you telling me what to look for. Thanks

 

[The Moonshiner]

Both cockerels

 

[Boldriniewy]

Thanks . Can you tell me what you look at to tell the sex? Is it because of their crown? Or other factors?

 

[sourland]

Early comb development in these chicks is pretty much indicative of the fact that they are cockerels. Secondary male feathering will start soon.

 

[ChickenShepherd_6116]

Thanks . Can you tell me what you look at to tell the sex? Is it because of their crown? Or other factors?

I don't know about The Moonshiner, but I could tell by the combs.