I apologize if this is not an appropriate question here. If so, let me know and I will remove or one of the mods can. I am training a horse for 100-mile endurance racing and as such, we are getting farther and farther from home on our rides. The dogs within 10 miles or so of me know how to behave. Outside of that, well let's just say we have had some pretty intense moments. I am looking for something to convince these kinds of dogs that horses are not chase toys!!
I have thought about pepper spray and someone elsewhere suggested ammonia but I have concerns of drift affecting the horse. About the best thing I can think of is an air/CO2 pistol. I DO NOT want to kill or even injure these dogs. I just want them to keep a respectful distance. I don't think a pump up pistol will work because there is usually more than one dog. Any suggestions on brands/styles to use to spook the dogs away and make coming at the horses unpleasant instead of fun. I'm not looking to spend a mint. This will probably be the only use for this specific pistol.
I am not at all knowledgeable about airguns so I have no clue as to how many fps is going to hurt but be very out of the ordinary to even penetrate the skin. These would all be no more than 10 to 15 foot shots. Any ideas or advice.