My chicks will be 3 weeks old tomorrow. I am really starting to notice a difference between some of them! I've read this is too early to sex them, but then I've also read that pullets start to get their wing and tail feathers sooner and the roos will have shorter/boxier wings at first? Mine are Wyandottes. A few of them are really getting feathered and a few are still quite fluffy. To compare...I think this one is a pullet? Front one...maybe a roo? He is also quite agressive with the other chicks, he likes to stand up, puff out his chest and fly in their faces. He's kind of a little jerk lol But so cute! The difference in their tail feathers especially is crazy to me!