Hermaphrodites in sheep happen but are rare ,personally i have seen maybe 3 out of maybe 50,000 plus lambs , Freemartin's again happen and you would as said never know , but all evidence says it is at a low level in sheep unlike cattle . I never suggested " locking in a stable " i said put all the sheep in over night only , ewes run with rams at tupping inside a shed is not uncommon all over the world and i have done it a couple of times if weather / grazing problems make it the best option . A ewe will not stand for a ram unless she is in heat and most rams will not be interested in ewe until she starts approaching that point in her cycle . If she is unable to cycle then the ram may check her out but nothing more , ewes running from a ram when not in heat can be seen all the time especially in younger ages