Weight and fleight: My roosters will top out 5.5 to 6 lbs and hens 4 to 5 lbs which is small enough for good flight. Also feathering of games is more functional for flight. Game hens not fly as much while laying but will do so for roosting and avoidance of predators. A consideration I will address is whether birds are of flying trim. I will be managing weight by occasional weighing and rationing of diet.
Training has proved quite easy with the game chickens. Insects were the enticement. Gallo del Cielo provided hints on how to do correctly.
For both issues above, breed (genetic factors) greatly affect weight and trainability. The games have been maintained in a near feral state for many generations where smarts for finding food has been maintained. My hatchery derived stocks have proven resistant to training although they will stand for ever waiting for free hanndouts. Games, if food not forth coming either get in your face or go foraging, sometimes some distance from area I apply feeds.