It looks to me like there are a number of diferent understanding (all different) of what question was being asked.
As stated I do see how it is confusing.
1) There are certain parts of a roosters body where the feathers grow differently and are shaped differently than on hens.
2) And depending on whether the chicken is male or female, the colour patterns, both on different parts of the body and on individual feathers can be different.
3) And on young chicks you can tell from the wing feathers as to gender--IFF they have the correct slow/fast growth genes. So it doesn't work for all breeds.