Horehound (Marrubium vulgare) for chicken (or other animal) feed?

Yesterday I learned that the name of a mint looking plant growing in an area the previous owners used as a chicken run is horehound. I'm wondering if it might be a good food for chickens. From what I've read other places, horehound seems to not be eaten by cows or sheep and is recommended for only occasional human consumption. I didn't see it listed on the "noxious weed" list but I think I'll propagate it anyway. It is said that it flourishes best in dry, poor soils so I'm thinking it'll be good to build soil. It is a perennial and over the last few years I have watched the plant get larger and larger. While it is nice to now know the name of the plant, it would be even nicer if it turned out to make an excellent chicken or duck or other animal feed since I've got plenty of dry, poor soil to plant it in and am waiting to get animals until I can feed them without bringing in external inputs.