All the dogs we've had on the farm we're cured out of chasing the birds after a "come to Jesus" meeting with me. Our older lab/Australian Shepherd cross we had for about 6 years before I got my first birds. She thought those 6 little ducklings were for her personal chasing and killing enjoyment. She learned pretty quickly that she would get in trouble if she chased them when I was around, but then she started sneaking. So I hid behind the duck pen one day and had my husband let her out. She immediately "snuck" over to the ducks and when she ran out to attack I jumped out and caught her right in the act. She got a big spanking, I chased her all over the farm for about 10 minutes and then she got locked up by herself for several days. She never looked at one of my birds after that.
My new rat terrier puppy also was getting into chasing birds. Started with little "woo-hoo" runs at them. Isn't that funny, look at the birds go? Then he realized the ducks would quickly give up and then he could just kinda sit on them and happily chew their wings up. Again, I caught him in the act, gave him a good spanking and chased him all around the farm with a several hour time out. Cured him.
They have to know you're serious and that YOU WILL catch them doing it. If you have two puppies I would work with them one at a time, especially a ringleader. It's a serious issue however. Nothing worse than a "pack" of neighborhood dogs that will run around and kills whatever they can find.
i've done something similar once:
i got my camera some fresh batterys, so i decided on a chicken photo shoot. i had the chickens and the pups outside (thats when i trusted them). Sydney, the blue heelers, greets me at the door. we walk together until i get half way to the barn. i hear the most blood curtling scream i've ever heard. i start to jog toward the barn, just when Nate, my banty standard mix flys outside onto another building right by the barn fallowed by Nikki, my aussie. i let her know shes never to do that again. i would have spanked her, but she made sure she had some distance from me. i yelled until my throught hurt. i then gave her the leash treatment; i put her on a leash everytime i went to the barn, until i got annoyed at chasing her down to put the leash on her. now both pups arn't alowed in the barn.
a few days ago, i had an idea. i cracked open the barn door just enough and put some wood over part of the opening. the hole was just big enought for my brahma hen to go through. just the other day, i find Sydney pushing the door open and going through
and just today i went in the barn to see the chickens. i left the door a bit open because its hard to pen and close the barn door from the inside. the chickens REALLY wanted outside, so my brahma hen steps outside. it only took 30 seconds before i heard nervous clucking followed by her speed walking inside. looks like Sydney rubbed off of Nikki, because Sydney was right outside.
i'm not looking for all this elaberate training things, when i told my dad i wanted a puppy, i wanted either a small herding dog (such as the corgi) or a large teddy bear dog like the mastif or St. bernard, but no, my dad wanted me to get a dog like a collie or border collie. i was ok with it until Nikki got into chasing chickens. now i almost don't want her. i never asked for a problem dog!
i've already lost a pullet to a dog before, i don't want that happening again!
I think you just need to realize they are in that "lilttle kid" stage and be willing to take time and patience to work with them. If you enforce the rules and boundaries in a couple months they will now what is expected and it won't be a problem. It was only a few months ago now that I had the latest problem with my puppy (he would have been about 5 months at the time) and now he is doing very well with the birds. I just watched him today "playing" with my turkeys. Hilarious. BTW, I also couldn't "catch" my puppy (he is SUPER quick) when he was being naughty. He would just run away from me yelling and act like "...whatever, you can't catch me! na-na-na." The day I finally got him, he was sitting on a duck chewing on her wing. I walked up to him very friendly like and he was all happy, wagging tail. So I was able get close enough to grab him and really give him a spanking. That made an impression let me tell you!
I do like what somebody posted on here with the saying "no" and walking between them and the bird. It really is about making them think you are the top dog.