Any guesses at breed? Hen or Roo?

[MemphisChickens]

I'm new to having chickens, in fact I've only had them for 3 weeks. They will be 4 weeks old in 3 days and the breed is unknown although some have suggested three of them are Red Star hybrids. I'm starting to get really paranoid and think they are all roosters. I am certain 1 is for sure.
Any feedback would be REALLY appreciated!!

 

[MemphisChickens]

 

[MemphisChickens]

More pictures of my chickens.
http://www.flickr.com/photos/shifting4now/

 

[magoochie]

gray one looks like a roo to me.

 

[tiffanya]

Not sure on breeds but I think it's too early to tell sex. Don't worry for now and give it a few more weeks to see.

 

[allieloveschickens]

Little gray one looks like an EE, and it looks like a roo. The red ones look like pullets to me

 

[FuzzyButtsFarm]

They all look like girls to me.

 

[MemphisChickens]

Some more head shots. Thanks for all the replies!

 

[MemphisChickens]

I hope this picture is bigger so you can really see the detail.