Horse and unicorn breeding

So a lot of foals were born today:
Curly Boomerang, by Bosco, out of Minnie, filly, chestunt tobiano, 6 stars, up for auction.
Spanish horse Bass, by The Black, out of Spammy, colt, light grey, 22 stars.
Spanish horse Hot Shot, by BK Hofasto, out of Chocolate Cream, filly, cherry bay, 47 stars.

Unicorn breeding again failed-.- Is it even possible to get a unicorn foal? But here is the failed foal:
Temple, by Ten Feet Tall, out of Blue Princess, filly, cherry bay, 12 stars, up for auction.