Any Fly Control is Good!

Here’s a great tip for keeping flies out of your barn and out of stalls.
Drop four pennies in clear plastic bags half-filled with water. Seal the bags and hang them at barn entry ways and just outside stalls.
Flies may start to come into your barn, but they’ll turn around and leave.
I don’t know why, but some say the water and pennies create a “prism” effect which splashes light in hundreds of directions all at once. The light reflections are supposed to cause flies difficulty in seeing, which is a “danger” signal to them.