Can't find an answer for this..(pics added)

I have looked and looked and cannot come up with any info. I'm wondering about my little RIR roo. Or pullet. I've thought he was a he up until several days ago when I noticed the combs on the leghorns he is living with. Two of the leghorns have a very large, pink, fat comb while the 3rd leghorn's comb is not as developed. The RIR's comb, though is about a quarter the size of the leghorns. They are all 4 weeks old. I was so sure the RIR was a roo.... Can it be that RIR's just don't develope as quickly as Leghorns? Call me crazy, but I was so hoping he'd be a roo.

Alright, here are the pics:
This one's a definite roo:

This one, too:

This one's under suspicion:

and here's the RIR I wanted to be a roo:



What do you think? RIR=roo or pullet?

 

Well darn it! My little RIR roo's comb does not have any pink yet. Guess he's a she after all. How 'bout that..I'm one of the few that get a pullet by mistake out of an all roo order. Go figure!

 

Not necessarily looking for a roo- I was just hoping this RIR would be one. I have 3 other leghorn roo's and a polish roo- so, I'm already up to my eyeballs in 'em!