I live in Alabama so the winters are not bad. Would a 3 sided barn/shed be okay? We are thinking 8x16 for 4 Nigerian dwarf wethers. I could add a half wall maybe 5 ft tall for them to go behind. Also, what is the best material to use on the sides? We used smartboard on our chicken coop but I don't know if that's okay for the goats. Thank you so much.