It can be incredibly frustrating to make any dog poultry safe. And it’s so hard when they eat your birds. I have LGD. My now 2 year old was SO hard. He would chase and chew any bird he could catch for a solid 1.5 years. Worked with him so much. Penned the birds separately. If any got out they were usually injured. Not always killed, because that wasn’t the motivation. Finally he was chicken safe after so much training. But not duck safe. Kept working with him, using a shock collar and going in the house so he didn’t know I was watching. Finally at 22 months he stopped. Possibly also related to neutering. Some dogs need time to mature. Some dogs are too prey driven and need to stay separate no matter what. Some dogs never kill any bird. My current puppy only licks birds. I still keep her away as much as possible, but one got in with her this week and is still fine. Was soaking wet with slobber but fine.
With a prey driven dog I’d use a two fold approach- yes, fence the birds. But also train the dog. A bird could get out. Training the dog makes that a less dangerous problem. There are many methods. Personally I find a shock collar most effective.