Gender/breed?

[VFfamily]

We got these chickens from my daughters preschool. 2 are starting to show red crowns. Is there a way to tell if they are roosters?

 

[chicken4prez]

If you can get better pictures that would be great!

 

[VFfamily]

Sorry my wife was having trouble putting pictures up. Here are a couple, hope they show a little better.

 

[chicken4prez]

1st looks like a Australorp. 2nd I have seen breeds like that but I can't place it... Maybe a mix... Anyone else?

The genders look like both are girls. Anyone else?