Flaxen
Flaxen is a trait that lightens the mane and tail of chestnut-based horses, turning them a pale yellow, cream or even nearly white colour.
Looks Like (Phenotype)
Flaxen only appears on chestnut-based coats. The body remains chestnut, while the mane and tail become noticeably lighter (like blonde hair). The shade can vary a lot. Some horses have only slightly lighter hair, while others have bright, almost white manes and tails.
Flaxen chestnut is often confused with palomino or even gold champagne, since they also have a lighter body and lighten the mane and tails of chestnut-based horses. The only way to know is if you know the heritage of the horse or if you test it's colour.
Variations
You may see lighter flaxen in some horses and very pale, almost white manes in others. The expression differs between individuals, and real-life research suggests multiple genes may influence it.
You can see quite some flaxen variations in Horse Reality, if you wish to try it out yourself!
Behind the Colour (Genotype)
The exact genetic cause of flaxen is not fully known yet in real life. However, it seems to behave like a recessive trait on chestnut.
This means your horse needs to be at least chestnut to have it
Related Colours
Chestnut | Palomino