Alpacas are quiet and usually friendly, and they don't need bomber fencing like a goat, and I have yet to hear one make any noise. I did read an article somewhere that horses that are kept alone are often more sleep deprived and live shorter lives. I think it was on "The Horse" website. I'll have to find it. I would consider an alpaca over a sheep or a mini donkey/horse/mule because of the soft feet, less feed, and no noise (we had a mini horse that neighed ALL the time when we rode off), but I think Alpacas can be expensive to buy. I've never priced one because we have 2 horses.