The thing that I wait on is color. Any structural faults (crooked toes etc) is easy to catch early. I look for dark brown-red color. They'll get paler as they get older and the paler ones won't do as well at the shows. That being said, if you have a paler bird that is superior type, keep it to breed to your dark birds. If you keep breeding dark to dark, you can end up with birds that are too dark. It's all a balancing act and experimentation.