Blue Chocobos are one of the hardest ones (so far) to beat and get. They are Ravagers and are found in The Archelyte Steppe ???AF. Their stats are as follows:
Chain resistance: 70
Stagger point: None (I know, right?)
Common drop: Chocobo Plume
Rare drop: ???
Status immunities: Poison, Fog, Pain,
As a pet, their racial attribute is Kill: ATB Charge, and are level one organic critters.