One maybe two is a pattern. I had a problem with Big Gulls pooping on the roof of my house and on my car. I live adjacent to a pond so when the ducks or geese are on the gulls perch on the neighboring houses until they leave. One day I got tired of having poop all over my roof and broke out my Tippmann A5. I tool about five shoots at the gulls on my roof. I didn't hit any but the impact of the paintballs against my roof and the report of the marker scared them off. Now the Gulls perch on my neighbors house not mine. Only have to go out to do this once a year in September. Teh Gulls know not to perch on my house. Goodluck. If they are Blue Heron they are protected species. Get some deer net and you should be golden. Try to keep your dog from killing anymore you may have a neighbor who decides to notify DNR. Which will cost you greatly.