I used the fly predators last year. No, they do not
bother livestock, their entire lifecycle is committed to eating the fly larvae,
hatching, laying more eggs in the fly pupae and eating the fly larvae. They are
not tiny flies. I believe they reduced the # of flies at my barn considerably,
but did not eliminate them. I'm using them again this year. Go to the website
& read more about them as you do need to have a damp manure pile suitable
for them. If you're the type that cleans everything up & there is no pile
somewhere near the barn, it might not work for you.
