Chocobo Help

Remember, as Chocobo grow older, they learn much slower until they eventually cannot learn at all -seemingly around 100 days or so- with dramatic slowdown long before that. If spread too thin, the "balanced chocobo" may not learn all the desired abilities, or even get close to 1st class in just two attributes, let alone all four.

Especially if this is your first generation, be wary of making a chocobo that is too average and useless. Balance is much better achieved in well managed training and breeding. Specialization in a particular attribute, though in the short-term may seem unbalanced, helps to produce much better baby chocobo's later on. It is easier to breed two chocobo with opposing attributes (a racer and a digger) to get a "balanced chocobo" then it is to attempt and do it all at once in the first generation.

Discernment - is a must for anyone who wants their chocobo to learn new abilities. This increases the likelihood of learning an ability. While it is still possible to learn an ability with low Discernment, the chances are slimmer and some abilities appear more difficult to aquire with low Discernment than others. It is possible to raise this to average quickly to learn two abilities, and switch the care plan to have a first class speedy chocobo. You may want to consider raising this attribute if you are interested in digging for treasure, as it increases the distance between how far you need to be to the chest to dig it up.

Your chocobo will auto-retire on day 129. (Note: At no point is it necessary to retire your chocobo in order to ride it, breed it or anything else. Retire it only if you wish to begin raising a new chocobo.)
You will be updated daily on your chocobo's status, as well, all cutscenes from the young chocobo phase will still occur in this phase.
On or around day 43, you may receive a message "Your chocobo is in the prime of its life." It was once "Your chocobo's attributes are at its peak" even though its stats could and would still increase after this point. It is assumed that this was a mis-translation that has been corrected.
On or around day 43, you may receive a message "You have done a magnificent job raising this chocobo. Now is the best time to improve its attributes. I must say, <name chocobo> is beginning to develop quite a distinguished air." You may or may not have both abilities by this day.
On or around day 64, you may receive a message saying something about how distinguished your chocobo looks. It has been shown that once you get this message the chocobo's attributes no longer increase through the use of care plans. It may still be possible to increase stats with carrots and the racing association's intense training programs however.

Because it can learn one story, doesn't mean it's guarenteed to learn another. Like Caiyou quoted, age plays a big factor and it's possible your chocobo is simply too old to learn anything else. My choco had learned both stories I wanted it to before it was 25, so I can't really give any other information about it based on personal experience. All I know is I fed mine aimed towards the "Digger Chocobo" work in the Wiki Guide.

but he was red and Top Strength, which is all that matters to Sandy Elfs, naturally. :D

chocos have driven me insane, like really, Blue male + blue female = black male WTF?