I actually struggled a bit with the colors for this painting. I wanted it to have bright, cheerful colors for spring. I personally love red flowers but felt red was too intense for this scene, so I stuck with softer colors like pink, peach, white, and yellow. Then there was the problem of the horses' colors. I wanted to do a horse color that was widely appealing. Bay seems to be a popular color for horses, which I understand because I personally love bay horses, but I felt the intense red-brown and black of the bay horse did not go well with the soft flower colors. I finally decided on a palomino foal and a gray mare. The reason for the palomino foal was because I wanted the foal to have a soft, sweet feel to it. Palomino incorporated the soft pastel colors of peach, pink, and yellow. Gray seemed to suit the mare because it was both strong and neutral. This gave her a sense of strength and protection while being a neutral enough color to not clash with the colorful flowers.
So, there you have it. Maybe you think artists pick colors at random, or whatever they like most. And sometimes we do. But other times colors are carefully selected, despite our favorite choice, because they create color harmony, symbolize something, or convey a message. And sometimes it's not always easy to decide which is most important. But, at least for this painting, you know why the colors are what they are. :)