RELEVANT GUIDE FOR FEEDING PATHS: http://i.imgur.com/WNH3nFv.jpg
Here is a list of the possible chocobo colours on a spreadsheet: https://docs.google.com/spreadsheets...gid=1434222506.
Some people have said that they've not had the same colour even if they have replicated the same feeds as others.
Going off what people have said on sites like reddit and the FF forums i've done some theory crafting regarding colours:
Things that we know:
6 Fruits in total, all based around the RGB colour values.
1 Fruit (Han Lemon) resets your chocobo's colour.
2 fruits for each color, split into lightening (less of color) and darkening (more of color)
People are reporting that results vary when using the same feeding combination.
Once you have met the requirement for a colour change, you will get a display message about the plumes changing
Things that we don't know:
How close to the Color Value you have to be to get your wanted Color Value.
How much each fruit alters the colour value's by.
Any limitations on feeding the chocobo multiple feeds at a time.
Things that may be happening:
The colour RNG is most likely based on the individual value each single fruit decreases and increases the color by, rather than a "chance" when the plume actually changes, it should range from between two values each time you feed it a fruit. (i.e between 5-10)
It seems like there is no limitation on multiple feeds so far, but we have yet to have confirmation on this. (A possible test for this is to feed a chocobo a stack of each fruit and see if it turns out soot black or snow white)(The limit may be 10 fruit, or 10 of each fruit per feed)
Hypothesis
Example: changing from Desert Yellow to Ul Brown.
Desert Yellow 216 175 80
Ul Brown 178 157 105
Feeding a chocobo 3-7 O'Ghomoro Berries can give you Ul Brown, but how come? It doesn't seem likely if we assume that each fruit will only alter a single value of colour.
O'Ghomoro Berries are said to deepen the hue of blue colours, which means the value of the blue color will increase, right? Yet, an increase ONLY to the blue color without decreasing the other values will lighten the overall colour, not deepen the overall colour.
For reference, RGB 255,255,255 = White, RGB 0,0,0 = Black. RGB values work off the light spectrum rather than pigment colours.
Pigment
RGB
This means we can safely assume that by deepening the color of the blue value you are not only increasing the blue value, but also decreasing the red and green values, which can be backed up by the Desert Yellow to Ul Brown feeds above. (Blue value is increased, while red and green are decreased.) By darkening the blue colour, you are also decreasing the value of the other colours.
By how much is still a mystery, but the way in which the colours are shifted has been worked out. feeding a chocobo an even amount of darkening fruits will EVENTUALLY make it reach black, while feeding it an even amount of lightening fruits will make it white.
To make things simple, i've put the fruits into a table ( + is an increase while - is a decrease )
So, using what we see here, we could feed the chocobo an even amount of lightening fruit until it reaches white, and bomb it with a single type of fruit to make it a specific colour. (Xephatol apple for a bright red, Valfruit for purple, etc)
Essentially this chart should allow you to make any type of colour you wish, within mild reason. It will be harder to make a colour which uses a mixture of all color's than a specific rudimentary colour, but this chart should help a bit.
I hope this provides a bit of insight and let's you fine tune your chocobo colour, I don't claim any of this is correct but it seems like it may be the case.
MORE THREADS
Many players have been on this topic since the start of the patch, support these players players trying to detail Chocobo Colour's below!