Below is the info we know so far from the patch notes:

The option Feed my chocobo has been added to the Chocobo Stable interface under Tend to My Chocobo. By selecting this option, players can feed their chocobo any of the following fruits:

Xelphatol Apple / Doman Pum / Mamook Pear / Valfruit / O'Ghomoro Berries / Cieldalaes Pineapple

Once fed, a chocobo's plumage will change in six hours (Earth time).
* The chocobo's plumage will change color depending on the fruit it was fed.
* After the chocobo's plumage changes color, feeding it a Han lemon will restore their plumage to their original yellow hue. Unlike other fruits, the chocobo's plumage will change immediately upon inspecting the chocobo stable a second time.
* No change will occur if chocobos are removed from the stable prematurely. It is recommended to feed them during times when the chocobo can be left stabled for extended periods, such as prior to logging out for the day.