Well, if you think about it, even in English we have separate words for ewe and ram. They're anglo-saxon; I think "hermaphrodite" only enters the language in the seventeenth century. So you might not have a word for "hermaphrodite" in shetland norse, and so might want a simple noun (on the lines of ewe and ram) to describe the phenomenon when it appeared in sheep. Especially in a culture where, as you say, they outnumber people. --Josh