red sunflowers

Well, I have lists of plants that rabbits/deer/slugs leave alone - but horses are not mentioned - so I'm no help am I? However, Sunflowers are not on the deer list - so that may be a clue that they, at least, WOULD munch on your flowers. Probably the answer might sound silly, but how about sacrificing one and offering to a horse to see if he/she likes it? Then you'd know.