Sex id help

[buffslat]

I have some chicks I got this spring. One is a Barred Rock the other is a RIR. The RIR is 13 weeks the Rock is 12 weeks. I thought both were female, but my Rock was doing a poor attempt at crowing this morning. I have an older Buff Orp and spent a little time trying to introduce them this morning. My RIR chased her a bit and then she laid down and the RIR mounted her and pulled the feathers on the back of her neck. The Rock did something that was like that, but it was more like standing on the buffs head with no feather pulling.
This seems very much like ale behavior to me. I've never had chickens or been around chickens in my life.
I have some pics I can post if that will help? Head, neck and wing shots.

 

[yinepu]

pics are always a plus!

 

[Poo On My Shoe's]

The hatchery Barred Rock males (like I have) are usually a lighter silver with a black bar, and the females are usually a very dark charcoal color that look like they have white bars. I do have a silver hen that I thought was a slow to mature rooster so the color is not 100% correct. I'm also fairly new to all this too. Pics would be great!