My chocos have the blues and hang their heads low. Im on the 2nd disc and I spent the 10000gil for the stables. But my chocobos won't go in them. What am I supposed to do? Whenever I try and move them to the stables chocobo bill says, "I wouldn't suggest that one"

....I wanna raise/race/feed my chocobos. They are all stuck in that fenced area.