yep, thats true, some breeds you can tell by there color.
Like the golden and the buff,
In buffs the females are lighter than the males
in golden the females are a brighter golden color than the males.
The crest sexing isn't reliable at first, because sometimes they can fool you! The best way to tell is around 4-6 weeks. Roosters will start to get red wattles and/or a V comb (which looks like little horns) and pullets definitely will not. The only thing a pullet at 4-6 weeks should have is possibly tiny flesh colored wattles, and many don't even have that. Some roosters will only get wattles or only a comb at first, then the second thing will show up later, but as long as they have one or the other then it's 99.5% sure it's a roo!
I've found this to be reliable for crevecoeurs, polish, spitzhaubens, and houdans! I think sultans are similar also because the only sultan I've had grew a comb at 6 weeks and he was a rooster.
Is this a roo??? I drove an hour to get this baby and told the guy I couldn't have roosters were I live and I think he sold me a rooster anyway! What does it look like to you? It's even getting what looks like spurs on the back of it's legs too!