What are the best ways to level up your chocobo?

[Eye_Gore]

'Reward' (feed) them special snacks when they are stabled (your FC will need a chocobo stable).

Else, killing lots and lots of mobs is probably faster (spirit-bonding sessions at Urth's Gift comes to mind...).

Is that why I always see people in that cave killing bats while I'm mining? Was wondering what the draw was to there.