It means in training. You can have up to 10 stars (*) FOr example if you have 1 star in jumping then you train your horse in jumping and he/she can get more stars that way. The more stars you have the better the horse is.
No. There are red and orange but as of yet, no pink stars.
you keep entering the contest and winning more stars
Go to the horse's page, click on "genetics", and the stars are listed there
A blue star indicates if a horse is purebred.
On Howrse NIB stands for Non inbred
this is how many stars a horse has, my highest is 25 stars (25*), but ATM in the game the highest is 27 stars a star shows that the horse is rather good, if your horse has over 100 gp in one catergory the it gets a star
On Howrse, GP means genetic potential. Genetic potential calculates how many green stars a horse has. The higher the genetic potential, the more green stars, and the better the horse is. Eventually the horse has so many green stars that he or she gets a red star, or excellence star. These traits are much admired, and when successfully bred down may produce a breed variation.
One can get a tattoo of pink stars in Edmonton from Crimson Empire Tattoo and Atomic Zombie. One can also get a tattoo of pink stars in Edmonton from Eye of the Lotus and Dragon FX.
You earn yellow stars by completing mini games, and the pink stars aren't out yet. But it is predicted that you have to pay money to get those.
It doesn't mean anything really. It's just an objective Howrse makes you do.
Quite a few horses have made it past 21 stars some horses have a hundred. - FrostyWizard