These characteristics are the same for juveniles of all upland species except pheasants. Also note the specks and more mottled coloring of the juvenile wing, compared to the adult. Refer to these pictures when you get to the sage grouse section. This rule applies to all birds covered here, except pheasants. Whether a rooster pheasant is an adult or juvenile is determined by the length and appearance of the spur between the foot and knee.
Sex determination is different for each species.
For pheasants, the difference is obvious. For sharptails, key indicators are coloration of the central two tail feathers and the feathers on the top of the head. The sex of a ruffed grouse is best determined by the length of the central two tail feathers, while sage grouse are sexed by the color pattern of the feathers under the tail. Just a few feathers and part of a wing or foot is all it takes for Game and Fish upland game biologists to know the age and sex of a harvested bird. You'll have the whole bird.