Don't be discouraged, educate yourself, learn from others who have good points, and adapt it to your situation. You can do it. I did it, with 2 of the allegedly worse of them hunters. I've got 2 Airedale terriers (King of the terriers), older Kimi is 5, and younger Rummy just turned 1. As you may already know, terriers were bred to hunt and kill. They have a super strong prey drive, some more than others. But I trained them to accept my birds as part of the pack. From the first day the chicks come in a box, they are each introduced to the dogs, and the dogs have learned to watch them and guard them, and protect them tenderly.
Rummy spends time watching over every chick in their brooder.
Rummy hunts mice and snakes in our yard, but he has a super soft spot for our batches of chicks. They have not hurt a single feather on them, and have been left 100% reliable alone with the chicks.
Kimi killed a baby rabbit, but he has not hunt anything else. He protects the chicks and adult chickens as they free range, but he doesn't have a 'love' for them, unlike Rummy.
That's Kimi tolerating a Cochin bantam on his forearm.
When we have chicks in the brooder, Rummy would rather spend the night watching over them, than sleeping in his own comfy bed. He really loves his chicks, and it is so unlike what a terrier is expected to do.
Of course, everything took training on my part, and I am the alpha in the pack, so I have taken very thoughtful measures in ensuring peace and harmony. From every detail, starting the day the chicks come home, to transitioning to outside, to having the dogs trained to guard them outside, everything takes time, and energy, but I believe anyone can do it. All it takes is patience, knowledge, perseverance, and determination.
All the best to you.