By "to bay" do you mean "to anchor"? Does the ending change the meaning of the word? If it means "sheep" is that singular or plural?
It also occurs in these contexts (all of which I got off the Net):
1. Kahvaltı sonrası Samanlık koyuna gidilir.
2. "Koyuna can mı, kasaba et mi?"
3. Maçı durduran orta hakem, koyuna düdük çalarak kırmızı kart gösterdi.
4. Koyuna çarpan sürücüyü çoban rehin aldı... (Part of a news headline, I think)
Sorry to keep pushing. I'm really trying to get a handle on the meaning. Of course, the name of the property may not be a Turkish word as all!!