We raise sheep, goats, chickens and ducks to supplement our income and altho we don't get many "drop-offs" they are not tolerated here. If throwing rocks and yelling at them doesn't convey a clear message that they better just travel on then the next course of action is more drastic and final. Most calibre of people that drop off unwanted pets are just too cheap to take them to the pound or too irresponsible to deal with the matter themselves.