I have just got a companion pony for my horse and they instantly got on, with the horse in charge.My normal set up is that my horse can go in and out of his stable and to his field, we have shut the stable off so they can get in the undercover area but no into the stable.This is working fine however the sun gets into the undercover area so they can not escape from the sun.Is it safe to open the stable door to let them both in out of the sun?Would I need to open both stable doors or could I just open one? I would like to open my horses stable door and let them both use it but worried it could cause arguments?