How to tell age of chickens

[R20]

Any way to tell how old a chicken is? Are there visual clues or signs that indicate rough age?

 

[sourland]

Feathering, elongated toenails, rough looking legs, excessive spur development can indicate elderly birds.

 

[Chickassan]

Rough large combs 'sometimes'.
Knobby toe arthritic toe joints.
Pretty much things you'd see on an older anything, they just tend to look a little bit weathered.