Hi mate,
You don't have to Colour feed if you don't want to, your bird is known as a red ground bird, if you don't colour feed all that will happen is that the colour will not enhance as much each time the bird moults.
The birds moult once a year around late summer and into autumn,
An adult bird can take upto around 10-12 wks, whereas youngsters normally 6-8 wks,
If you do decide to colour feed you only need to do it through the moult normally starting about 1 month beforehand as it takes a little time for the caraphyll red colour food to get into the birds system,
As the bird grows new feathers the colour is pushed through the quills of the new pin feathers and is how the feathers get the colour, the colour food is a powder and is mixed at a ratio with the birds drinking water normally mixing a few mls of colour to 1 litre of water or alternatively can also be mixed in with the egg food but to me this is not as effective.
Reason being that youngsters on there first moult do not moult fully, the flight ( wing ) and tail feathers remain until the following year hence why it doesn't take so long to moult as apposed to an adult bird.
A bird under 1 year old is known as unflighted and an adult is flighted,
On An adult flighted bird its flight ( wing ) feathers wil normally turn from white to a yellowish colour,
This is how we normally tells first year unflighted birds to an adult flighted bird