i just fed my chocobo just with berries and only untill new feathers grew and i have a different way.
The start was the same then here https://imagizer.imageshack.us/v2/18...903/LuEMw9.png

Destert Yellow -> Cork Brown -> Ul Brown -> Gobbiebag Brown -> Shale Brown -> Gobbue Grey

then it changed -> Lilac Purple -> Plump Purple, till that point it was like feeding 1 or 2 times, after that I had to feed 8 times and i got Gloom Purple.