I just read up on different kinds of mints being a sort of pest repellent in the coop. I just planted a bunch of Nepeta (purplish/blue flowers) last year. They are awesome in your garden as they attract tons of Butterflies and Hummingbirds. Last year, the plants were covered with small butterflies. It is a perennial as well. All I do is cut back in late fall after flowers are gone. Not to mention, we have 2 cats...and catmint (Nepeta) is like catnip. Just clip a few sprigs off and give to the kitties. They love it!! So the interesting thing is, since i have so many of these and they are relatively cheap to plant..and looks beautiful...I read that they repell pests..being in the mint family. Now I have 5 things i can use these for. Beauty, Butterflies, Hummingbirds, Cats and now my coop for the chickens. Oh...and deer and rabbits are repelled by the plants so none get eaten!! Hooray! Also, I have lavender everywhere. Reading up on that as well I may just cut some and put it in the nest boxes to relax the girls time to time. Just thought I would share this with others. I am sure alot of people already know about these but in case you didn't. BTW...I use peppermint essential oil spray for a natural bug repellent on myself up here in the woods and it works wonders...stands to reason why mint would work in the coop.