A fun, interesting, unique strategy game! I think it particularly shines because of its charm - the music, clopping of the horses and nicknames all help to create a relaxing feel and I felt attached to my horses.
Some interesting drawbacks with the bushes, fences, and horses getting in each others' way.
And I quite liked the game art.
I think a couple of things that would've been helpful (I know you were probably very crunched on time, being a game jam):
- Tutorial levels that slowly introduce mechanics and number of horses
- Labeling horse attribute above them, so you don't have to click on them to see, like the way you did the arrows
And one fun little thing would've been to be able to nickname the horses yourself, to further personalize the game and provide attachment to your pets.
Overall, awesome stuff!