There is this comparison
OR
Saw this on a British chicken forum for older chicks
Heavy Breeds
2 weeks: Female shows a little tail feathering 1/8" to 1/4"; male shows no feathering at all.
3 weeks: Female better feathered than the male - tail and shoulder plumage up to 3/4" long. Male much less feather than the female; shows more fluff and has very little tail, if any.
4weeks: Female shows feathering down back and chest and on thighs, and the tail of a utility breed is 1"+ long:male much more fluff, hardly any back plumage, and a small tail now appearing.
5 weeks: Females legs shorter and thinner than males; her body is longer, tail longer, feathers better; males legs longer and stouter, body shorter and more cobby, tail stumpy, possibly 1" long, not much feather on back and wing bows.
6 weeks: Female hardly any fluff; male much better feathered now but still some bareness at shoulders, back and wing bow.
8 weeks: Female smaller comb than male, abundant plumage, short thin legs,longer tail 1" to 2", and a bold and dashing manner: male taller and larger, almost completely feathered, with comb and wattles increasingly redder and larger.
Light Breeds
2 weeks: Male begins to show tail quite plainly
3 weeks: Difficult to distinguish by tail size, though male usually shows stronger, perkier tail; male grows feathers almost as fast as female.
4 weeks: Male's comb is larger and redder than female's
5 weeks: Male is a little longer in the leg than female, but comb is growing much faster
6 weeks: Males appear taller with definitely stouter legs; pullets have smaller legs and therefore seem closer to the ground.
8 weeks: Definite difference in combs and wattles.
Both
12 weeks: For all types, male seems to stand higher on much stouter legs; headgear definitely red and bigger; spurs usually larger; definite difference in saddle hackles - male's are pointed at the end, female's rounded.