If you really want better judgements on sexing maybe post pictures of the whole chick and some together. For example coloring on the Barred Rocks gives them away much easier than their combs.
Herp Lover these are better pictures. Both barred rocks are a bit light in coloring. The wash on their legs is very light so that is why I am guessing roos for both. I have 2 BR's (6 weeks also) and they are a darker. Leghorns will have big combs when older but the first one is REALLY big and so is the second one but what a difference in size.