Pullet or Cockerel?!?!

[mimi2012]

Helppppp!!!!
I'm having trouble determining what sex my 2 chicks are!
These are the pictures; the first 2 photos (same chick, just different view) is a rhode island red and is 4 weeks old.
The 2nd&3rd photos (same chick) is a black australorp and is exactly 3 weeks old.↓↓↓





Anyone have any knowledge about chicken sexing???
HELP PLEASE!! (sorry if the quality is bad >x<)

 

[Habibs Hens]

still a bit early but they seem all pullets

 

[aoxa]

Both are pullets

 

[Happy Chooks]

Both are pullets

x2

 

[mimi2012]

Really??!! Both are Pullets?!

Thanx everyone!!!!!!!

♪*Chicken dance*♪