Have you ever had a kid with AWESOME coloring, then looked at the same kid 3-4 months later only to realize it’s coat color has completely changed? This is actually pretty common. Take a look at this young buck. His dark chocolate spots lightened to a beige. (Excuse the dirty face and beard… he is a buck).
Those peachy, light red colored kids will usually lighten to a beige or light cream. Often the reddish browns will turn out medium or light brown by a year old. I’ve even had a medium brown kid with chocolate moonspots turn into a solid light brown doe. The moonspots are genetically still there, but they aren’t visible unless you shave the goat and then only barely.
This phenomenon isn’t limited to just goats, but is common in other species as well. In horses, most aren’t registered until they are older for this very reason. Attempting to register a foal would require the breeder to have a pretty good knowledge of how the coat will change as the foal ages.
This doeling below was a mousy gray with some darker areas. The next picture shows her at a year old and she’s a light tan with darker brown areas. (Side note: This doe is the daughter of the doe above. While her mom darkened as she got her adult coat, this one lightened.)
Take plenty of pictures when your kids young and again at 6 months old. With time you’ll start to see a pattern with how the colors lighten and change so you’ll be able to have a pretty good idea of how they will look as adults.
If you’re interested in learning more about livestock genetics I recommend the book A Breeder’s Guide to Genetics.