Well, for example, if one is blue - A blue cockerel will develop dark color patches around the shoulders, neck, saddle, etc. Plus they're simply develop saddle feathers. (small, short, and triangular on the back)
The males will be quite green, iridescent, and also develop small hackles on the back (usually very pointed and shiny)
Some other things to look for are neck and tail base. A female will have feathers simply flow from neck to back, back to tail. A young male will have short feathers at the neck, then the feathering sort of "halts" at the joint of the neck and shoulders, then at the joint of the tail and back, is another halt. These are both because the hackle and saddle have not finished growing, and are what create that "smooth" outline/flow from one part of the body to the other.
With the head - Another thing is eyes. If a bird has a good spacing in front of the eyes, making it look mean or hawk-like, or a decent hooding of feathers over the eyes, or a lot of red around the eyes - It is quite likely a male. The two bottom ones are possessing these traits.
The males will be quite green, iridescent, and also develop small hackles on the back (usually very pointed and shiny)
Some other things to look for are neck and tail base. A female will have feathers simply flow from neck to back, back to tail. A young male will have short feathers at the neck, then the feathering sort of "halts" at the joint of the neck and shoulders, then at the joint of the tail and back, is another halt. These are both because the hackle and saddle have not finished growing, and are what create that "smooth" outline/flow from one part of the body to the other.
With the head - Another thing is eyes. If a bird has a good spacing in front of the eyes, making it look mean or hawk-like, or a decent hooding of feathers over the eyes, or a lot of red around the eyes - It is quite likely a male. The two bottom ones are possessing these traits.
