Hi Virginia Feeding up to 1/2 cup of Pure Apple cider vinegar (not the flavored kind) often helps keep the flies from biting = perhaps because of the smell. The was one of the studies that my sister Linda and her husband did at their research farm in the 60'. You start with about a teaspoon mixed with water on a bit of grain and then gradually add more until to get up to between 1/4 and 1/2 cup. We found the horses actually preferred the vinegar to plain grain - like salad dressing :))
Robyn Hood
