Just remember, even with all your NO TRESPASSING signs, the animal cant read. If it is attacking you, then fire away. You might be able to dispose of them if they are a creating damage, but that would depend on the local "leash" laws. Discharging a firearm within the city limits is a different ball game alltogether and you should check your local ordinance.
No such thing as a stupid question. What is stupid is not asking it.