Chicks challenging each other

[dirtbath]

I have two week old chicks. I have no idea what sex they are. They are obviously sick of their brooder already because when I take them outside, they get super excited and jump, hop, and almost "challenge each other" like in a cock fight. Now they are only two weeks, are they just being silly little chicks or does this mean they are roos?

 

[kipper]

Pullets and cockerels will both do this. It's the pecking order. Roos will do it more, though. Cute when they stretch their little necks up, huh?

 

[dirtbath]

It's so much fun watching them get so excited about something! They just get so silly in the fresh air!