fly repellent through feed

I do use fly predators at home and I have fly spray of course....

I was curious if anyone used any products?
How well do they work?
What brand they use?
What does it cost?
Can I put 2 of my horses on it?
Does it test legal for show?
Does it change their mood or eating habits?

I used just plain garlic for awhile. It was an actual horse supplement, I forget the name, but I can check for you. But I'm not sure I noticed much of a difference, except my horse's breath really smelled

I've also tried the Equi Spot stuff, its like flea and tick medication for dog and cats. Its a liquid that comes in a little applicator and you put some a the poll, along the topline, and down each leg. I did notice a difference there, I still applied fly spray, but I think it was nice as just a little extra protection.

Add whole grain or textured feed to their diet, then get some chickens. Free eggs and they spread the manure so no fly breeding areas. Some of the feed through fly controls are hogwash, the dielectic something or other earth ones. Basically a fancy word for sharp crystals, but the fly eggs get laid after the horse poops and once it hits the ground the poop aint moving around so it wont be cutting up any fly eggs. The concept of feed through fly control is to put poison on the manure. Id rather have chickens spread it out as soon as it hits the ground. Also go with the shiney glue traps put low to the ground to catch biting fly, not the add water fly baits. All they do is lure non biting house flys in.

I fed 1/4C Apple Cider Vinegar a day, all last summer and saw really good results.
Of course, the flies still loved Lacey but they didn't like her nearly as much as they like her off the ACV.

It was pretty cheap too, a few of those giant jugs of ACV from the grocery store lasted all summer.

I have used the equi-spot stuff and I do think I remember that working well. I tried the bands with Riley but he had a reaction to the citrinella and his whole leg swelled up :(