Check the comb and wattles: roosters usually have larger, redder ones
Look at the tail feathers: roosters often have long, curved sickle feathers
Observe the hackle feathers: roosters typically have pointed neck feathers
Watch for spurs on the legs: roosters usually develop them
Listen for crowing: roosters often crow, though not always
Notice body shape: roosters are often more upright and muscular
Look at behavior: roosters may be more territorial or dominant
Check feather coloration: roosters are often brighter or more vivid
Compare size with other birds of the same age and breed
Examine saddle feathers near the back: roosters often have pointed ones
Consider age: young males may not show all rooster traits yet
Confirm by vent sexing or DNA testing if certainty is needed