I use a blend of peppermint and lavender. I mix 1-2 ounces of each along with 2 ounces of glycerin (food grade) in a 32 ounce bottle. Shake before each use. The peppermint is for rodent deterent, and the lavender is for snakes. I don't know if it is that, or other things I do, but I don't have rodents or snakes. And since it makes the coop and area around where they are fed in the run smell good, I keep doing it. I also add a few drops of lavender oil under their nesting pads now and then. I know as a scent for humans and dogs, it is relaxing, so I figure why not?
Edit to add: I mix it up pretty strong. A 32 ounce bottle lasts a month, and I use a fine spray fairly liberally, daily.
This is the peppermint I get. There us also a lavender, but I get a different one that I also like for my pillows.
https://www.amazon.com/dp/B003C54M9A?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1