I am not from your area but bee sure to keep your hives away from where your horses are. For some reason, the smell of horses seems to bother bees and the horses don't seem to run away from the bees when attacked.
Bees do not attack horses unless they are protecting the hive, so distance is the key.
Just to bee safe, I would keep them a couple of hundred feet apart.
On the other hand, my bees do not care about my cows grazing right up to the hives. Occasionally the cows will smell the entrance to the hives and bee reminded why they should not do that.