Yeah . It was just the one. The best we can figure is that there may have been some stray piece of chicken feed or dog food that the one chicken happened to get too close to when the dog was near. He's food obsessed, so our guess is he did a quick snap/bite on my poor chicken's head. (The incident was under the porch roof. Our security camera vaguely caught it but it only takes one frame per second.)
So sorry to hear! It is difficult to lose a hen. When we started our little farm, really had no idea how hard it would be to protect the hens from predators. We live on a wooded ravine, so that makes it extra difficult. We have everything from mink, to coyotes, and of course our aerial (protected) enemies.
). Now, this could have something to do with their individual personalities, because my male is a people-pleaser, but he was the one that loved to chase and pin them down, and then he would go hide from me because he knew that he wasn’t supposed to do that. My female just copies whatever her brother does (yes, they’re siblings) and doesn’t have a care in the world about listening to people. So, I think that when he stopped chasing them, she caught on and didn’t do it anymore either. 
Hello!
My two border collies are young, about two years old, and they do not hurt my chickens. It wasn’t always like that though. They had already killed one of my Guinea fowl and a young peahen I hatched, as well as attacked any other bird that came in their yard. I’m not exactly sure what happened, but pretty much overnight they just stopped attacking them and completely ignored any bird in their area (except for the grackles and doves
I think that they need to know that they are going to get a severe punishment if they chase or hurt any of the birds. That helps them stop doing it. I’ve heard shock collars work well, although I’ve never had one. I simply give them a firm spank on the rear end, and that seems to work too
