I board horses and have a problem with nats. They're getting active early this year and I want something I can use on the horses that's non toxic and safe. Something with no odor would be ideal so I can spray them as needed. Also, I need something to use in the barn so the horses aren't bitten all night long when I put them to stable.
Nats will get active as soon as the temperatures warm and there is moisture in the air. As our nat control article explains, there are a lot of things you can do around the property. But for the areas you've listed as most important, I would recommend the Permethrin. It's odorless and safe to use on horses and will last a day or two depending on how strong you make the formulation. It can be sprayed inside the barn as well or fogged with one of our Foggers if the area to treat is large.