I can't tell them apart!!!

[LindaJean]

I need help. I have several breeds of adolescent pullets (and the incidental roosters - but that's another story). There are 5 RIR and 5 Red Sex Link. They are all 6 weeks old and I can't tell them apart. It only matters because some are going to a friend's house Sunday and I wanted to keep 3 RIR and 2 RSL. I'm sure some of you know how to tell them apart. It looks like some are a darker red and some have a much darker beak. I'd like to think those are the RIR but I'm not sure. Suggestions appreciated

 

[fried green eggs]

The rsl may have some white in the feathers. RIR are pretty solid colored and darker.