I agree but imprinting definitely has a part to play. I know a lot of collies who herd birds just because they HAVE to. Unrelated though, i worked with a german wireharid pointer a few years ago in the kennels. oh my lord. I had to give up on it, it was just totally untrainable and a total nightmare the whole time. He would jump up to the top of the cage and get his paws through the top of the door then let go and hang himself, barked all day, chewed the doors off, fought with every dog it saw, jumped out of the 9ft outside run, was UNWALKABLE, pushed you over and nipped at your anytime you went near it and would barge past you to get out of the cage when you opened it to put food in. We eventuially had to put it in the "dangerous dog" pen purely because he was such a nightmare but he was so dopey he would not go to the other side of the pen to get locked in so we had to put his food in then walk around to the otehr side and call him and run for dear life to get to the other side to close the door before the dope ran back in to greet you. The owner was asked to go elsewhere if she ever wanted to go on vacation again. That dog scarred me for life lol
As with most situations and likely with the OP as well, the weak link is usually the owners control over dog if training is required. My German short-haired pointer is the smartest dog I have ever encountered yet still has the potential of being a numbnut when riled up. OP as well will need to suppress the numbnut drive and that may require providing the dog with occasional diversions and developing control. Even the typcial guard dog has a numbnut mode and that may need to be diverted to control losses of birds.