Understand, but this was the 60's and I didn't have much choice in the matter. I'm not advocating this form of protection, just sharing my experience.
I definitely agree one should check regulations. Thank you for pointing that out! I didn't think anyone today would even consider doing this, so I overlooked the law aspect.
I don't know how effective grandpa's method was. I don't know how many were repeat customers. If you kill one, another will take its place.
Most, if not all, raptors are protected by law and one could get themselves into a whole, big ball of worms by molesting one. I always advocate proper fencing and secure buildings for livestock over killing wildlife.