Training Ones Chocobo

[Beckett]

So the question is, why is it that my friend and I can train our own and each others Chocobos back to back, essentially getting double the training per hour, but not our third friends?

This confused me for the longest time as well. The reason why you can't train your third friend's bird is because he just put it in the stables. He can train his bird right away, but for other people there's an hour cooldown from when he puts his bird in the stables and you being able to train it. It's super weird, but that's the answer.