Just a tiny point, James. In BE, a wether is certainly a male sheep, but one which has been castrated. A male sheep which is 'complete', in dog breeders' argot, is a ram.The word is in our dictionary with two L's: bellwether. It is an indicator of the future or a leading indicator, much like harbinger. It can be good news or bad news. It is not always a positive sign.
As a side note, a "wether" is a male sheep. Traditionally, the sheep that leads the others wears a bell. He is the "bellwether".