Dragons stats are different than human stats. For simplicity sake there will be no difference between same color of dragons, since dragons will not have their own character sheet.
Golds:
Brawn: 10
Flight: 6
Smarts: 10
Flame: n/a (a flame thrower is 14)
Bronzes:
Brawn: 9
Flight: 6
Smarts: 9
Flame: 20
Browns:
Brawn: 8
Flight: 7
Smarts: 8
Flame: 18
Blues:
Brawn: 7
Flight: 9
Smarts: 7
Flame: 16
Greens:
Brawn: 6
Flight: 10
Smarts: 6
Flame: 14
Brawn: Shows how strong and tough a dragon is. Also is relative to size, the bigger the stronger.
Flight:Shows how nimble and agile a dragon is in flight, does not necessarily have to do with speed.
Smarts: Shows how good the dragon is at thought process and memory.
Flame: Shows how long and strong a dragon's flame is. In the case of Gold's a flame thrower is given instead.