Coyotes are back. Apparently there is a small dog among them. Stood out from their singing very noticeably. Either that or a coydog, if they sound like that. they were just the other side of the road...
I saw a homemade version of coyote rollers on the interwebs (picture on FB, not sure if I could find it again but a google search might) the other day.
Basically a cable strung across the top of the fence with a smaller diameter length of pvc strung on it, and a larger diameter one outside of that.
Personally I love my fido-shock, but in areas where it isn't practical for whatever reason, the roller idea might be very good.