Anyone had any experience of these.........

[electricalkid]

when I say these I mean the small battery (or mains) driven anti vermin pest control thingymagigs that you often see advertised in the weekend newspaper supplements. Promising that the item emmits an ear piercing noise not audiable to humans which aissupposed to keep rabbits cats dogs away. I'm looking to instal such a device to deter my neighbours chickens, goats dogs and horses from coming too near my garden - any ideas or suggestions would be very welcome - thanks in advance

 

[Thermo]

ive put them in for people where they have problems with foxes digging up lawns and cats etc. seem to be quite effective for the 25 or so quid they cost.