No, it's not too late. I have German Shepherds and when Loki was a pup, despite my working closely with him, one day he grabbed one of my birds and started to pluck her. He seemed to think she was a squeak toy. I grabbed him and scared the ever loving crap out of him by giving him hell. I think he thought I was going to beat him. I kept a very close eye on him and after a year, it got to where then the chickens are scared by something, they come running to Loki and stand under him for protection. It takes training, consistency and time but it can be done. One of my Shepherds is 1/8 wolf and saw his first chicken when he was 7 years old. He is a very well trained dog and it didn't take him long at all to understand the chickens were now part of our home. There are many posts on here about how to train your dog. Do NOT tie a dead bird around its neck.